The first step to being able to play Europe in Ruins: Reinforcements, is simply registering on the forum. If you haven't done this yet, do so now by clicking 'Register' in the top left menu:
***** Your Forum name must match your online Relic / Company of Heroes in game name exactly. This is case sensitive.

Once you've received your confirmation Email, you will be able to post on our forum and register for the Launcher.
Registering for the Launcher will allow you to log in and play using the launcher program included in your download. You can register for the Launcher by clicking the link in the upper left hand menu of the Forums (above the leaderboard):

Now enter your desired launcher Username and password, then confirm the password.
***** Your Launcher name, and Forum name must match your online Relic / Company of Heroes in game name exactly. This is case sensitive.

Now simply submit and confirm your launcher registration.