All you have to do is send Bitcoin Cash to any of the listed addresses. Your winnings will automatically be sent back to the address you sent the funds from! No registration of any kind is required.
On August 1st, Bitcoin forked into two different versions of Bitcoin. One is still called Bitcoin, although it is significantly different than what Satoshi described in the original white paper. The other is called Bitcoin Cash, and is the currency that this website uses. To learn more about Bitcoin Cash, visit bitcoincash.org.
If you already had some Bitcoin on August 1st, you already have Bitcoin Cash. You can use this recovery tool to gain access to it. If you already have some Bitcoin, you can use www.shapeshift.io to convert it into Bitcoin Cash.