Board Thread:Off-Topic Discussion/@comment-25147000-20150320032731/@comment-32500188-20150516191552

Are you adding a new page or editing an existing one?

If you're adding, go ahead and get the page started/added, then go back and edit using the drop-down menu beside the big purple button at the top of the article and choose "Classic Editor". From there you can look to the side of the editing page and add your categories in the related box.

Editing an existing one: same big purple button, same option. ;-)