Specifying CMS linked pages

Hello all,
I am creating a portfolio page. I want to link a thumbnail image to a CMS page, but I don’t see how to specify which “item” in the CMS collection to link to. I would have multiple pages within the CMS.

For visual reference
If you scroll to the bottom where it says “more work”. I want to link to a CMS item

site

appreciate the help!
Mike