After successfully completing Episode 1 "The Phantom Menace", you will unlock episode 2, "Attack of the Clones" in "Episode Select". You will get this achievement after completing all 5 episode 2 levels in story mode. You do not need to watch the cutscenes, although you can if you want.
In case you're stuck in a certain section in the episode, here is a thorough walkthough of how to complete episode 2 by PackAttack04082: