In your back-office, tab Manage> General > Permissions.
- Add an account, i.e the email address of the contributor that wishes to work on this event, then click on Add.
- You can limit his/her actions on your event by checking the different boxes.
- By checking "Access restricted to account's own guests" your contacts are hidden from your contributor's back-office.
- You can add as many contributors as you wish.
- You can know the last connection of each contributor.