to register your Wallet you must have your EOS tokens in a Ethereum wallet (not an exchange). The best option is to use Metamask. Go to eos.io then downscroll to "GET EOS" button. Hit Continue.
After that search for "Register" tab, then hit "EOS TOKEN DISTRIBUTION" button.
You have to be logged in your Metamask. Then Hit "REGISTER EOS KEY" Button. Then copy and paste both keys just for you ina safe place. Then enter the private key in the inbox and hit "I HAVE SAFELY BACKED UP MY PRIVATE KEY" button. The Metamask will popup.