Robert - without a bit more detail, I'd tell you the following: if you want explicit "ownership" privileges for only one user, and no other user/s to see files/folders, then the easiest way is to use the console and two commands: "chown" and "chmod".
>chown will change ownership of a file, and all subordinate contents explicitly to a single user. This can be useful when you want to conceal anything from others. Used in conjunction, is "chmod" which changes the permissions. For instance:
>chown -R "owner" " file
>chmod -R 700 file (this will allow only the specified owner to Read, Write or Execute any file contained. Variations are "Full Control" for Owner, Read for Group, Nothing for Others. 755 will set to Full, R/W, R/W. You can do this through the interface if you want to point and click a lot, but console and CLI is fastest.
Maybe that will help-