Well, that depends: do you have a programmable DVD player?
Here is how my DVD player works (a basic RCA model I bought at Walmart):
When my DVD player goes on, the main menu (of the DVD player) has a subcategory under "play" (I click on that and the submenu comes up) that offers a "program play" option. Then I choose the order of sections I want to play, such as title 1, chapter 3, then title 2, chapter 4, etc. Ther title/chapter correspondances for Cathe DVDS (except for the new ones and ab hits, which aren't posted yet) can be found under the descriptions of each DVD, through the home page.
For the new DVDs, you can figure out what chapter is what by choosing the "info" button on your remote control. This will display the title/chapter that is currently playing. You can quickly go through the workouts chapter by chapter and write down the title/chapter correspondences.
The actual "mix-and-match" feature that is on some Cathe DVDs is less useful, in my opinion (but works even if you don't have a programmable DVD player). Choose the mix-and-match option from the main menu of the disc. Then you can choose one segment to play first. When the segment is over, you are taken back to the mix-and-match menu and can choose another segment (ad infinitum). Not as slick as programming through your DVD player, and too choppy for my tastes, but it works (I think, though I've never used it).
Hope this helps...if not, sorry!