I bought the first video from MARS music for $25. The production is pretty good showing one guy working a 424 MkIII. Occasional close ups of the 424 controls. The video is supposed to be general enough to cover all the cassette based PortaStudios. I have a 414 so it worked out pretty well.
Overall, the video is well done but pretty basic. If you have already successfully made a recording with overdubs, skip this video. If you have just opened the box or you are still confused between the mixer and the recording sections, get the video.