Instructional DVD has 30 demostration videos, catagorized on 4 pages.
What is best design so end user can pop DVD into machine, bring up appropriate page, select demo from thumbnails, play it and automatically return to page when demo finishes?
'Best design' isn't exactly easy - one's favourite is 'not good enough' for others
One of the things that i would include (on each of those 4 pages) is a "play all"
button for all the demos in that section.
That way users can either select their favourite demo or play the entire set demos
of that category.