The details are here. Just make sure you follow the details carefully.
You can also win $200 in hotel credit, but that’s a separate, additional promotion. Make sure you sign up for an account with them first, then follow the instructions in this post to enter to win the $200.
If enough people sign up for accounts, they will also offer a SECOND $200 in hotel cash you can win.
Good luck and may the giveaway odds be ever in your favor!