Use your UNC email address when registering for the first time to assure you are signed up for the full, institutional account (this is free to you). It is best to use your primary account rather than an alias. You can check for your primary account at selfservice.unc.edu, under "My Aliases." You can also try email@example.com if you have trouble.
You will create your own password.
Quick Start after registration (from the Overall FAQ Help Guide):
Getting started link from online HELP guide includes these topics: