From the xCenta Dashboard, click on Tools > Admin in the top right of the screen.
A new screen will appear. From the Administration screen, click on Manage Users.
You will be directed to the page below. Click on the 
A new page will appear, click on the Roles tab. The roles created will be presented, allocate the role required from the list provided and click Save.
If you are unable to follow these instructions, you may not have the required user permissions. Please contact your Site Administrator.