losen the screws that lock the strings at the saddle. tune the guitar just like any other. the floyd should ideally be parallel to the guitars body, so you may have to adjust the screws of the springs in the back of the guitar and retune until the trem is in the disired position. when this is done, tighten the screws at the saddle to lock the strings again.
after that, fine-tune the strings with the finetuning-screws on your bridge and your ready to go
if you have more questions: just post!