Applying for sunrise applications is a little different than registering normal domain names. In most cases you will need to prove you are the legitimate owner of a trademark using a SMD file that can be obtained through the Trademark Clearinghouse if your brand is registered there.
Follow these steps to apply for a domain in Sunrise:
Locate the "Launch phase registration" link
Then locate the extension you are trying to register your domain in and click the extension.
On the next screen upload a valid SMD file
On the following screen submit your contact info and the domains you would like to register and click "submit SMD request"