Setup an Account User

Steps

Log in to your account.
Select My Account from the drop-down under "Welcome" in the upper right.
Click Manage Users found under Security.
Select Add New User.
Select the appropriate Role Type, fill in the user's information, and click Add New User

It may be helpful to have the New User available at this time as their username, password, and email are set. The password and email may be updated at a later time, by either the account owner or by the user themselves.