(A good guide is installed by default. It will be in the start menu in the AutoGK->Tutorials folder.)
Open file: - Open the main IFO file if you want to transcode and entire DVD, and choose the appropriate program chain (PGC) by seeing the duration.
(Unfortunately it seems to pick the wrong chain - tho it mentioned 40 minute PGC duration, final O/P was 2 hours long!)
Choose a Subtitle track if you want a subtitle track burnt into the avi.
Select output size as per your requirement. Better to choose file size than the percentage stuff.
In advanced settings, choose the minimum width option and give value as 576.
(So, the video will be resized, with a min width as 576 pixels. In case the output size is big enough, a bigger resolution will be automatically chosen.)
Aspect ratio, frame rate, cropping etc are automatic. If you feel auto crop may not work, press Ctrl-F9 to go to hidden options, and change the number of frames and the begin frame of the auto crop detection. You could also change the "Enable Standalone support" to ESS if you prefer - that is supposed to be more compatible.
"Add job" and add any more jobs to queue if you have more than one PGC to process.
Processing takes roughly 1.5x realtime with an output of 150 MB file for one hour of video (roughly 300 kbits per second!) on a PIV 2.4 GHz.
But this low bitrate makes the output look like VCD quality. . .