Joomla installation error: Please enter a package folder. Unable to find install package
First of all, my apologizes for my english, it is not very fluent.
Now, my answer: 
Have you checked if this version of CiviCRM is compatible with your host PHP version?
CiviCRM package is not an Autoinstaller Package as many other extensions: components or plugins.
I think the process to install is:
-Upload the compressed CIVICRM package (Check than is a Joomla version) to the 'tmp' folder of your Joomnla installation. Uncompress-Expand it.

-Now, in your tmp folder there must contains a folder 'com_civicrm/
In administrator/extensions/install-uninstall/install from directory add the /com_civicrm/ subfolder at the end and click install.
If everything goes right you will get a 'component successfully installed'.

The link to Civicrm help : https://docs.civicrm.org/sysadmin/en/latest/install/joomla/

Good Luck!
Francesc