Login as the admin of the site.
Go to the Photo Albums -> Settings admin page and check at least: Table VII-B 0,1 and 2.
The most important setting is Table VII-B1, this makes sure the 13 people can only destruct(!) their own albums/photos. Check in Table VII-A Album admin and upload photos for the userlevel the 13 are.
Make one parent album, say it is named Hans
Make the 13 sub-albums, set its parent to Hans and their owner to the login ids of the 13 photographers. This can be done easy by selecting it on the Photo Albums -> Album Admin -> Edit Album Information screen.
The 13 users will be able to make their own sub-albums.
Displaying photos in more albums together in one display is not yet possible, but is a future enhancement. This will take some time.