You can add more colleagues by clicking on "Invite new user" and entering the e-mail address of the desired employee. In these operations, you already assign a corresponding role. Then you have the option to add a personal message that will be displayed in your invitation email.
When you click "Invite", the colleague receives an email with an invitation link. To complete the invitation, the colleague must enter their name and set a password for the account. If you accidentally invited the wrong person or used an incorrect email address, you can delete the invitation by clicking the appropriate entry in the Users tab and selecting “Remove”.