A Video CD (VCD) can contain (almost) as much video as it can contain audio: a 74 minute CD can contain some 73 minutes of video (the rest is filled with some control programs and indexes).
When you use the TMPGenc wizard, it allows you to select the required output (VCD, ntsc or pal), then select the video source, then do some extra tweaking (usually size conversion and/or cutting the movie into two or more parts of less than 74/80 minutes), and then select the location to save it to. It'll also show you how large the resulting file would be, and if it'll fit on a CD at all.
Being a wizard, it *should* be pretty simple. Then again, I have a lot of experience, and know what I'm doing.
