Ok, first I would recommend browsing the PB Fitness forum, there are a lot of good insights posted in there. It just may take a little digging.
Next, do not restrict yourself to the set/rep guidance in the book, go with whats feels (mentally/physically) good. As a beginner just start light, 5 lbs., and move on from there. After you get a feel for what you can do, you can start experimenting more with different weights and reps.
For an example we'll talk about lunges:
Start with body weight and try for 20 (10 with each leg) if that kills you do less reps, if it is too easy do more or add weight like with 5 pound dumbells in each hand.
The best advice I can give about weight lifting is to experiement and remember that form is the most important thing to keep from getting injured.
"Most men stop when they begin to tire. Good men go until they think they will collapse. But the VERY BEST men know that the mind tires before the body and push themselves beyond all limits. Only when all of these limits have been shattered can the unattainable be reached." ~Dan Gable