To assign an alert out to users you will have to assign it to the specific roles the alert applies to, you can not assign an alert to individual people.
From the xCenta Dashboard, click on Tools > Admin in the top right of the screen.
A new window will appear. From the Administration screen, click on Manage Site.
A new page will appear. Click on the
icon.
A new pop up will appear, click on the specific roles, then click OK.
If you are unable to follow these instructions, you may not have the required user permissions. Please contact your Site Administrator.