To add a new user go to Settings > Users, and click on New user at the top of the page.

You will be able to search for the contact by last name/first name (if they are already in your contact list) or enter their email address (for a new contact) and then define one or more roles for them.

If the user is not registered for your event as a team member, enter their email address to send them an invitation. The user must log in or create an account to accept the invitation and become a user of the event.

In your list of users, click on the user's name or on the "More" icon (vertical dots) which appears when you hover over a line to view the user's details, modify their access rights or delete them.