Summarize:

You may want to increase or decrease reps and sets based on your experience and fitness level.  Remember, a lower rep range for a more inexperienced body builder is 1-5 reps. Medium rep range is 8-12 reps. Higher rep range is 15+ reps. The higher the weight you use, the bigger your muscles will get. However, you will want to increase reps and weights gradually so you don't injure yourself. A good rule for muscle building is to start at a lower rep and increase the weight before increasing reps.   Beginners should try using lighter weights with lower reps to get started, then gradually increase.
Choose your rep range, set range, and weight.