This tutorial assumes you already have an Atlas account. If you don't you can get one here: GET ATLAS HERE.
Login to your account at Roundcubeplus.com.
LOGIN HERE (Opens new tab)
After signing in you will be taken to the customer area click the Log in to Atlas Control Panel link.
To add another server profile go to Default Profile.
Click Create New Profile.
Next enter a new profile name, for example: "Server 3" and hit Save
After you save you will see your profile list. To start using your new profile, click the Switch button and it will take you to a blank Atlas account. You can switch back to the Default Profile (server) at any time from this Atlas Profiles page.
Now that you have a clean slate, you can setup Atlas as if it was a new server account.