5 grams before and after you train. As for brand, make sure you get "micronized" and you just have to try it to see if it upsets your stomach. I've used lots of different brands and i've never had a problem with my stomach.
Most people make it much more complicated then it has to be. Personlly I don't use the stuff, but i know lots of people that use it all the time, they never cycle on or off, or do any of that loading stage nonsense.