Server 2008 File Share

Hello,
Probably a pretty easy question for you guys. Im setting up some file sharing from a domain controller overseeing 6 pc's. Within the share you have your basic share permissions, and then you have your ntfs permissions. Could you please explain the differences a little. The way I see it the first basic permission is what give the user access to even get the share folder open, and the the ntfs share permissions are more for what they can do with the folder and files once the get in. Thanks in advance for the help.