Yes, you first need to complete the purchase of the tickets. The details requested at the time of purchase are for the account holder placing the order, which are the same details used to create an account on the website.
After finishing the purchase, log in using those credentials and fill out each credential with the details of the person who will actually be using it.
To learn how to assign each credential, visit: How to assign my credential?
For more information, please contact our support team.