A reminder to update your character level to 80 in your character profile to be able to signup for level 80 events. If you do not, you'll get the confusing error message that you need to Create a New Character to signup.

To raid with Relentless, you must read and sign the raiding rules on our forums

WoW has a brand new, exciting class in deathknights. Unfortunately, that means this signups doesn't know about deathknights. Please, deathknights create your character as a warrior, but put a comment in the raid signup that you are a DK-tank or DK-dps.

First create your character under your Profile. Then from the Main Page, select the raid(s) you wish to signup for and queue your character from there. The leader of the raid will move people from the queued list into the list of people for the raid. People left on the queued list on the day of the raid are considered backups.