BBY/ABY is used to position items along the Star Wars Timeline. BBY refers to Before the Battle of Yavin. ABY refers to After the Battle of Yavin. The Battle of Yavin in Episode IV: A New Hope occured in 0 BBY/ABY.
Before Luke can be a Jedi, he needs to learn from Yoda! This fully-illustrated level 2 reader retells the classic scenes from The Empire Strikes Back where Luke learns to use the force for the very first time.