There are some video on youtube.

 Drewtech has some videos on their site, also on their utube channel

 Here's a PDF guide to BMW CIP programming with Maxisys Pro: http://www.auteltech.com/u/cms/www/201501/282132017pvy.pdf

 What brands do you mean? Only BMW?

 Depends on what you refer to: with 'programming' there is flashing (with the J2534) which is BMW/Benz only right now (GM maybe?) from Autel using the MaxiSys software and guidance and there is 'all others'. There is no guide that includes them all I guess, it's brand specific. If you go to the car manufacturer site and you choose the flash options, you will get software from them (after paying) to use in conjuction with the pass thru unit.

Programming in Autel on functions side etc. is very extended. It is brand specific and sadly there is no one standard for it so also not one manual or something like that. It is 'learning along the way' if you come across cars that need programming or let you have a change to do play around with it (watch what your are doing, it can be harmfull)..

Finding out 'exactly'  what MaxiSys can do; man, you are in for a real job then. It can o major stuff, and the functions are on the brand logo's of your diagnose screen. Under the logo for let's say GM, you will find this little arrow, pointing you to the PDF for this brand. In it are all the functions, for all the cars of GM, sorted in a way that will give you quite a job to get a hold of.  Basically said, it can do about all major things that are possible to do on a car, but it has a few gaps and a few flaws and definately can use some improvement in some of the 'side sections' like key programming etc.

Can Bus; http://en.wikipedia.org/wiki/CAN_bus for the general stuff but if you want to do measuring in it just google youtube for some directions or take a training on it; which will pay for itself in no time if you are to work a lot with it.