The Clean & Jerk is an explosive Olympic lift that pretty much works your entire body (e.g., core muscles, legs, shoulders), since it combines elements of the Deadlift, Front Squat, Overhead Squat, and Military Press (just the lockout portion). Note: It is not intended to be an “arm exercise”. You should not be pressing the weight overhead (i.e., your arms simply lockout as you drop under the bar) and you don’t use your arms to pull the weight off the ground at all, but you should already know that if you use good Deadlift technique. It is a great lift for working on your power, vs. just your brute strength (like Deadlifts and Squats do). Power = Weight x Distance / Time. Or think of it as Strength x Speed.
Here are a series of videos on Clean technique, Jerk ladder practice, and then working the full Clean & Jerk. These movements are very hard to describe, so it does help to break them down and to see video of the movements.