Okay... the template page is where to define how a finl content will look. If your're making a blog, it will be the final blog post page. If it's an ecommerce site, it will be a product page.
You "can" create such page by hand but Webflow will ultimately only link to this page when you click on a teaser of a content (ie a teaser of a blog post in a list of posts). Everywhre in the cms you can dynamically link to "the post" and it will go to this page.
So every collection has a template page. You don't need to use them all. For example, chances are that is you have categories for blog posts, you won't use the page that shows one category... it' pretty much useless, unless your categories have to be explained.
So a page is for static pages, or dynamic lists, and collection templates are for final content. Sometimes in the CMS world final content are called NODE or FULL NODE.
If anything is still unclear, please don't hesitate to say so. It's simple, but can be confusing for CMS newcomers. But it's extremely important that you feel comfortable with those concepts to work at ease with Webflow CMS.