Every page may have a “talk page”, including pages that you aren't allowed to edit (the official content pages). It's similar to Wikipedia that way. A “talk” page is a way to discuss ideas without making changes to the page you are discussing. These talk/discussion pages can only currently be accessed in the desktop (not mobile) version of the wiki. It's the second tool icon, showing the two speech bubbles (Start a Discussion). It creates a page like this - rebellion

When you click on it, and there is no discussion yet, you'll need to create a new page for your talk/discussion.

The best practice for a talk page, is to sign off any comments you make with your signature (use the “insert signature” icon on the edit toolbar) - as multiple questions/comments/answers by multiple users can get confusing when they are split up and addressed separately.