(Continued-1930 character limit)
Once your Share permissions are set, choose the security tab of the file object properties screen to further define the security access permissions. There are 6 basic security attributes that can be directly defined here - Full control, Modify (RWXD), Read&Execute (RX), List Folder Contents, Read, and Write. If you choose the Advanced button towards the bottom, and then view/edit individual entries in the advanced screen, there are 13 seperate security attributes that can be modified there.
When a user accesses a file or folder through a share, Share permissions are first applied and then any security permissions that are set on the specific objects are used for further access control. The resulting access will be limited by the most restrictive permissions from both the share and security settings, with any Deny settings overriding all others.
Hope this helps, -Ewing