To add link to any page created with Pineapple Builder to a button or text link, open "Pages" tab and click more options for the page you wish to link to:

Copy of slug (URL) will be copied to your clipboard. In this case it will be /pricing

Now pick eg. button component to which you want to add a link and click "Edit"

This will open the tab on the right with more options. Here you can paste from the clipboard (ctr+v) link

Done, now when you preview this button on the page it will open your subpage.