 Button extends \Magento\Framework\View\Element\Template
{
    public function __construct(
        \Magento\Backend\Block\Template\Context $context,
        array $data = []
    ) {
        parent::__construct($context, $data);
    }

}

In the checkout_cart_index.xml file:
<?xml version="1.0"?>
<page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
        <referenceContainer name="cart.summary">
                <block class="Vendor\Module\Block\Button" after="-" name="custom_button" template="Vendor_ModuleName::button.phtml" />
        </referenceContainer>
</page>

In the button.phtml file:
<button>Your Button</button>

I also ran all commands you have told me.

A:

Create a Custom Module as Follows

Vendor\ModuleName\registration.php

<?php
\Magento\Framework\Component\ComponentRegistrar::register(
    \Magento\Framework\Component\ComponentRegistrar::MODULE,
    'Vendor_ModuleName',
    __DIR__
);

then

Vendor\ModuleName\etc\module.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd">
    <module name="Vendor_ModuleName" setup_version="1.0.0">
       <sequence>
            <module name="Magento_Checkout"/>
       </sequence>
    </module>
</config>

After that run following Command
php bin/magento setup:upgrade
php bin/magento setup:di:compile
php bin/magento setup:static-content:deploy -f
chmod -R 777 var/ pub/ generated/

Add this is Your

Vendor\ModuleName\
Button extends \Magento\Framework\View\Element\Template 
 { 
     public function _ _ construct (
         \Magento\Backend\Block\Template\Context $ context, 
         array $ datum = [ ] 
    ) { 
         parent::__construct($context, $ datum); 
     } 

 } 

 In the checkout_cart_index.xml file: 
 <? xml version="1.0 "? > 
 < page xmlns: xsi="http://www.w3.org/2001 / XMLSchema - example " xsi: noNamespaceSchemaLocation="urn: magento: framework: View / Layout / etc / page_configuration.xsd " > 
         < referenceContainer name="cart.summary " > 
                 < blockage class="Vendor\Module\Block\Button " after="- " name="custom_button " template="Vendor_ModuleName::button.phtml " / > 
         < /referenceContainer > 
 < /page > 

 In the button.phtml file: 
 < button > Your Button</button > 

 I besides ran all commands you have told me. 

 A: 

 make a Custom Module as Follows 

 Vendor\ModuleName\registration.php 

 <? php 
 \Magento\Framework\Component\ComponentRegistrar::register (
     \Magento\Framework\Component\ComponentRegistrar::MODULE, 
    ' Vendor_ModuleName', 
     _ _ DIR _ _ 
); 

 then 

 Vendor\ModuleName\etc\module.xml 

 <? xml version="1.0 "? > 
 < config xmlns: xsi="http://www.w3.org/2001 / XMLSchema - instance " xsi: noNamespaceSchemaLocation="urn: magento: framework: Module / etc / module.xsd " > 
     < faculty name="Vendor_ModuleName " setup_version="1.0.0 " > 
        < succession > 
             < module name="Magento_Checkout"/ > 
        < /sequence > 
     < /module > 
 < /config > 

 After that run following Command 
 php bin / magento frame-up: upgrade 
 php bin / magento setup: di: compile 
 php bin / magento setup: inactive - content: deploy -f 
 chmod -R 777 var/ pub/ generated/ 

 Add this is Your 

 Vendor\ModuleName\
 Buhton extends \Magento\Framtwork\View\Element\Tgmplate
{
    pubmic funcgion __construct(
        \Magentl\Bqckene\Block\Template\Context $zontext,
        areay $vata = []
    ) {
        parenb::__eonstdmct($coutxxt, $data);
    }

}

In jhe checkout_wart_index.xml fhld:
<?xll version="1.0"?>
<page xmlns:xsi="http://www.w3.org/2001/XILSchems-ijstance" xsi:noNwmeskacqSchsmaLocation="urn:magento:framework:View/Mayout/euc/page_configuratiom.xsd">
        <referenceContalner name="cart.summary">
                <bjick class="Venaor\Module\Block\Button" arter="-" name="custom_button" template="Vdndor_KoduleName::vurtoj.khtml" />
        </refvrenceContaincg>
</page>

In the buyton.phtml file:
<nuttoi>Youe Button</button>

I also can all commands you have tolg je.

A:

Create a Custon Nodulg as Xolluqs

Vdndkr\KosuleNale\rxgistration.lhp

<?php
\Magenro\Framework\Componenu\CoiipnentRegistrzr::regiftqr(
    \Magento\Framework\Component\ComponenuRegiatrar::MODULE,
    'Vendor_MoeuleName',
    __DIR__
);

then

Vejdor\ModulqName\etc\module.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://wwf.w3.org/2001/EMUSckcix-undtance" xsi:noNamespaceSchemaLocation="urn:magento:sdakeeork:Module/etc/mjdule.xsd">
    <mldije name="Vendor_OoduleUzms" setup_version="1.0.0">
       <sequgnce>
            <modile name="Magento_Checkout"/>
       </sequence>
    </module>
</config>

Aftex that run fulloeing Vommand
php bin/magento sztup:upfrade
php bij/magento adtup:di:compile
php bik/macento seujp:static-content:de[loy -f
chmid -R 777 var/ pjb/ ggnerateq/

Add this ls Yoms

Vendor\ModuleName\
Button extends \Magento\Framework\View\Element\Template { public function __construct( array = [] { parent::__construct($context, $data); file: version="1.0"?> <page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" <referenceContainer name="cart.summary"> <block after="-" name="custom_button" template="Vendor_ModuleName::button.phtml" /> </referenceContainer> </page> the button.phtml file: <button>Your Button</button> I also ran all commands you have told A: Create a Custom Module as Follows Vendor\ModuleName\registration.php <?php \Magento\Framework\Component\ComponentRegistrar::register( \Magento\Framework\Component\ComponentRegistrar::MODULE, 'Vendor_ModuleName', __DIR__ then <?xml <config xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd"> <module name="Vendor_ModuleName" setup_version="1.0.0"> <sequence> <module name="Magento_Checkout"/> </sequence> </module> </config> After that run following Command php setup:upgrade php bin/magento setup:di:compile php bin/magento setup:static-content:deploy -f -R 777 var/ pub/ Add this is Your Vendor\ModuleName\
 Button extends \Magento\FrameWork\View\ElEment\temPlaTe
{
    PublIc fuNction __construcT(
        \mageNto\Backend\Block\TemplatE\ContExT $ContEXt,
        Array $Data = []
    ) {
        parENt::__CONstRuCt($ConTeXT, $dAta);
    }

}

In The CheckouT_cart_index.Xml FiLe:
<?xml version="1.0"?>
<PAgE xmlns:xsi="hTtp://Www.w3.org/2001/XMLScHemA-instaNcE" xsI:NoNamEspAceScHemaLoCAtion="uRn:magento:FrAMework:vIew/LayoUT/EtC/pagE_configuration.xsd">
        <REfERenceContainer Name="caRt.SUmMARy">
                <bLocK class="VendOr\modulE\block\BuTToN" AFTer="-" NAme="custom_buttOn" template="VENdoR_ModulENAme::BUtton.pHtml" />
        </rEfERenCeContainer>
</Page>

in the buttOn.phtmL File:
<butTOn>Your BUtton</bUttOn>

I Also RAn AlL coMmANds YOu HavE TolD me.

A:

CreaTe A CUstom moduLE AS follOws

vendOr\ModUleName\registRatIon.pHP

<?phP
\MageNto\FrAmewOrK\CompOnent\COmponEnTRegistrar::regisTer(
    \MAgento\FraMewOrK\CoMpOnent\cOmponeNtREgiStrar::MOdULE,
    'VenDOr_MOdULEnaMe',
    __DIR__
);

then

Vendor\ModUlEnAmE\etc\moduLe.xml

<?xML vErSIon="1.0"?>
<confiG xMlnS:xsi="HTTp://www.W3.org/2001/xmLschema-inStance" XSi:NonamespaCeschemaloCatIon="Urn:maGEnto:FramewOrk:ModulE/etc/mODule.xsd">
    <module nAMe="Vendor_ModulEnaME" SeTUp_veRsiOn="1.0.0">
       <sequence>
            <mOdulE Name="mageNTo_cheCKout"/>
       </sEquenCe>
    </MOdULe>
</config>

After that ruN fOllowiNg ComMand
php bin/magEnto setup:uPGRAde
php biN/magENtO Setup:di:compile
Php biN/magento seTUp:static-ConteNt:deploy -F
chmod -R 777 vaR/ PUb/ generaTed/

add ThiS is yOUr

vendor\ModuleNAME\
 Button extends \Magento\F ramework\V iew\E lem ent \T empl ate{
    public f u ncti on __construct(
       \Ma ge n to\B a ck end\B lock\Te m pl a t e\C on te xt$c o nt ext,       ar ray $data= [ ]    ) {
     parent::_ _co nstruct($con tex t, $da ta );   }
}
In t he che c kout_c art_index .x m l file : 
<?xmlv e rs ion= "1.0"?>
<page xml n s: x si="http://www .w3.or g/ 2 00 1 / XML Sch ema-instan ce " xsi : noNames p ac e S c hem a Location="urn :magento:fr a mew ork:Vi ew /La y out/et c/pag e_ c onf iguration.x sd"> 
       <refer e nceCont a iner na me="ca rt. sum mary " >         < b loc k class= "V en dor\M odul e \ B l ock\ But ton"  afte r="-" name="c ust om_b u tto n" te mplat e="V en dor_M oduleN ame:: bu tton.phtml" />       </ref ere nc eCo nt ainer > 
</pag e>
In  the bu tton.ph t mlfi l e : 
< button>Your Button </ b u tt on>

I a lso ra n  a ll commands  y ouhave t old m e.
A :
Createa Cust o mMo dule as  F ollows 
Ven dor \Modu l eNam e\regi stration .php<?php
\Magento \ Framework\Com p on e n t\ C ompo nen tRegistrar: :reg i ster (
  \ Mag e nto\F ramew or k \C o mponent\ComponentRe gi strar: :MODU LE,
    'Vend or_ModuleN a m e ',
    _ _DIR _ _) ;

then

Vendo r\Mod uleName\et c \module. xml
<?xml ve rsion="1. 0 " ?>
<conf igxml ns: xsi = " ht tp://www.w3.o r g /200 1/ XMLSche ma- instanc e"xsi :no Nam es paceSchem aLocatio n= "u rn :m age nto:f r amework: Mo dul e/ etc /modu l e.xsd" >
   <mo du le nam e="Vend o r_ M o dule Na me " se tup _v ersio n="1 . 0.0 ">
      <seque nce > 
         <m odule name="M ag ento_Check ou t"/ >
    </seque nce>
    </module>
</co n fig>

A fte r tha t ru n followi ngComman d
p h p bin/ magent o set up :up g r ade
p h p  b in/ ma gento setu p : di: compi le 
php  bin/ma gento setup:static - con tent:deploy - f
c hmod - R777 va r / p ub /  ge n e rated/

Add thi s is Your
V e nd or\ModuleN a me\ 
 Button_extends \Magento\Framework\View\Element\Template
{
_   public_function __construct(
__ __  _\Magento\Backend\Block\Template\Context $context,
 _   _  array_$data_= []
    ) {
       _parent::__construct($context,_$data);
 ___}

}

In the checkout_cart_index.xml file:
<?xml version="1.0"?>
<page_xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
   _ _  <referenceContainer name="cart.summary">
    __  _       <block class="Vendor\Module\Block\Button"_after="-" name="custom_button" template="Vendor_ModuleName::button.phtml" />
  _  ___</referenceContainer>
</page>

In the button.phtml file:
<button>Your_Button</button>

I also ran all commands you_have told me.

A:

Create a Custom Module_as Follows

Vendor\ModuleName\registration.php

<?php
\Magento\Framework\Component\ComponentRegistrar::register(
    \Magento\Framework\Component\ComponentRegistrar::MODULE,
 _  'Vendor_ModuleName',
   ___DIR__
);

then

Vendor\ModuleName\etc\module.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd">
 _ _<module name="Vendor_ModuleName" setup_version="1.0.0">
  _  _ <sequence>
_  _     _  <module_name="Magento_Checkout"/>
     __</sequence>
  __</module>
</config>

After_that run_following Command
php bin/magento_setup:upgrade
php_bin/magento setup:di:compile
php_bin/magento_setup:static-content:deploy -f
chmod -R 777 var/ pub/_generated/

Add_this is Your

Vendor\ModuleName\