If you mean the difference of sets and reps..
Reps: How many repetitions you do of an exercise (For example: Pull ups 10 REPS, that's 10 pull ups)
Sets: How many times you do reps (For example: 2 sets of 10 pull ups, that's total of 20 pull ups)
A few more examples:
4 sets of 8 push ups (You do 8 push ups for 4 times, or 32 times in total)
2 sets of 5 pull ups (Total of 10 pull ups)
And so on..