5/3/1 Assistance Workouts?

^x2

Seriously just buy the book it answers almost all questions, but if you have anymore, read all the articles here at
T-Nation( there are a lot of them ) and if that thosent answers it all, then you can go to this thread:

I can give you a quick answer regarding supportive excercises:

The most normal thing to do is roughly something like this: 3-5sett of 8-12reps for supportive excercises.