[Creation Q] Building a page and linking it to another?

Hello everyone!

I feel like a bit of a dummy asking my question, as I have created one page in the past, but I forgot the exact process and need a refresher (and once I receive my answer, I will be sure to save it so that I won't have to pester anyone again).

There is a live-action adaptation of a book coming out. I would like to create a page for said adaptation and then *link* it to the page of the source material. How would I go about doing this?