How to add to Gitbook?

I want to add a sentence documenting the location of the MacOS version of a file to the VST page in the new handbook on Gitbook. I've read https://handbook.musescore.org/about-the-handbook/using-gitbook#change-… but I don't see the Edit button as described at https://docs.gitbook.com/collaboration/change-requests. I also don't see a gitbook repo at MS's github. I'm logged in to gitbook and I understand that while the site is published, edits are disabled and so a CR needs to be made. But how? Am I missing something obvious?