Drag your movie to the main menu screen to create a "play all" button. You can double-click it to open it up on DVDA's timeline and add chapter markers there, or you can use the markers you created in Vegas. Once you have the markers placed, go back to the main menu screen and right-mouse-button click on the play button you already created. From the popup menu choose "insert scene selection menu". You'll be able to choose how many chapter buttons per page. You can then navigate into those menu pages to rearrange, change the thumbnails, chapter titles, etc.