Login to the Admin Panel
Every domain has a default admin account. The email id of this account will be postmaster@<your domain>. The credentials for this account will be sent to you via email on the registered email id for your organization. Use these credentials to login to the Admin Panel for your domain.
To provision users in a domain, you can use one of the two options:
Provision Alias ids
Alias ids have to be associated with an existing user account. The alias ids for users can be set using the Admin Panel.