Can not edit sub sites.

I have set up a sub domain at my host provider. Then we added a new sub site. When we go to edit it, we get a 404 error because it can not find the “*.com/wp-admin/” page on the server.

I see that the “wp-admin” folder exists for admin site when looking at the folders at my ftp site. However, I do not see “wp-admin” folder in my subdomain.

The question would be is, how is my sub domain directed to the wp-admin page.