All of the Sources that you want to merge have to be present continuously during the process. The easiest way to accomplish this is to copy all but one of the discs to VIDEO_TS folders on your hard drive first. Then you can use a minidisc as the first Source and the ones you copied to the hard drive folders as the other Sources. Load the minidisc as you did before, make all Title, audio and subpicture stream selections and settings, then click Next. On the second page you can set chapter ranges and re-arrange the playback order of the Titles. If all is in order, click on the Source Folder icon and navigate to the VIDEO_TS folder that contains your next Source. The screen will automatically jump back to the opening Merge page. If you are new to DVDFab, a look through the Tutorial will answer many questions. It can be accessed through the red link in my sig, among other ways.