How many workouts ?
Depends on intensity and duration.
Depends; if you're fairly new to weightlifting, i'd suggest doing full body workout 3 times per week, with a rest day between each session. I'm no longer a beginner, but I still conform to this regimen. The key to this is to do the highest weight possible per each muscle group (for gains, again, this is based on personal preference) but one set only.