How do I render a block programmatically with the standard template?
If you want to render blocks directly from twig you can use:

Twig tweak 8.x-1.9 https://www.drupal.org/project/twig_tweak

You just need to install it.
The block should be configured on "admin/structure/block" page.
Example how to use:
 &lt;dt&gt;Block:&lt;/dt&gt;
  &lt;dd&gt;{{ drupal_block('system_powered_by_block') }}&lt;/dd&gt;

Add this code directly in the twig template file.