How do I use a Page Template from my Theme on my Custom Post Types

Explains the settings that need to be modified in your theme files to make your theme page templates available for your custom post types.

From WordPress 4.7, you can now assign Custom Page Templates to other post types along with the ‘page’.

To achieve this in addition to the Template Name header, the post types supported by a template can be specified using Template Post Type, as following:

You can find out more about this from this WPTavern article and this article from the Make WordPress Core.

Adding the above to your theme files can be done by replacing the files in a child theme so your Child theme files will overwrite the ones from the Theme source. You will also need to make sure you activate ‘Page Attributes’ under Advanced Options, Supports in your particular Pod.