Please check the attached new project.
Actually, you don't have to make any new configuration for templates, instead, I only move some templates to certain place such as the 'product list' template should be put underneath 'group' template, so after 'group' template and its sub-template 'scroll' , page navigation template loads more products , then 'product list' template starts to collect through all products.
When you edit 'scroll' link template, 'windowscroll' action has been added in Advanced tab > Action section (at righ hand side), and setting to 'Repeated AJAX calls ' = true, this will ensure that page can be scroll down automatically , moreover, you should be noted that 'Repeated AJAX calls max. count' = 0 by default, that means it will auto-matically scroll page down until there is a failure (no more pages), but sometimes, if there is too much pages being loaded then it will raise a 'out of memory ' issue, in case you should set a fixed max. count, also, you should set a fixed page count with page navigation template for the limitation of pages.
You still can refer to the below topic link for understanding: