Hi turtles21
If you connect to the FB link, you "like" the page and choose their option (listed on the left) to enter their comp. Their entry box may ask you for name, address, email address etc.
Sometimes you just "like" their page to enter, and they will either:
1. send you a message via facebook that you have won
2. send you an email to say you have won OR
3. Post info on their wall to say that you have won, and you need to reply to the email address they provide.
I hope this helps