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.
It's tough to be a droid! When TIE fighters attack the Ghost, it's up to the cranky astromech droid, Chopper, to keep the ship together. If only his crewmates would decide whether they want him to repair the shields or the intercom...or the shields...or the intercom.