how do i edit the device start page?

Using the standard software supplied by Philips, the device start page is automatically created for you whenever you save the file in NEOedit. A program called NeoHacker (and another called NeoSynch - but I haven't tried that one), can be used to change any page to the start page. You simply create all your pages including a desired start page, and save this in NEOedit. Then use NeoHacker to change that page to the start page and save with a new name. (By default the new name will be the old name with "hacked" added on.) Load this hacked file into NEOedit (but DO NOT save it), and download to your Neo. If you save it, the start page will get lost. So if you need to make changes go back to the original (un-hacked) file and make your changes there, then go through the hack again. Kind of a pain, but it works.

I think Philips wanted the Neo to be easier for the average user. For power users, it would have been nice if they would have had an option in NEOedit to turn this "auto-start-page" feature off.