Quick answer, RTFM.

sorry, just kidding. This one is easy to miss on your first remote.

More detailed:
Step 2, I believe - "Edit buttons". By dragging buttons on the Watch and Listen pages, you are actually moving the pages. What I mean is - If you drag the DVD button on page 1 of "Watch" to page 2 or wherever, you actually move that whole device to the new location.

Now, if you are just talking about individual pages, such as DVD page 3 needs to be DVD page 2 it's a bit different.
Right click on DVD, select "add new page".
Right click on DVD page 2, select copy. - Paste that on the newly created page to get it out of the way.
Right click on DVD page 3, select copy - paste it on page 2.
To delete, right click on the specific page and select "delete". Simply hitting delete on your keyboard will initiate a deletion of the whole device.

or...
Hire a pro!