you need permission to perform this action with access denied at share

All three users, Barb, Bob, Brian, in the advertising department received 'denied access' and 'you need permission to perform this action' while attempting to access the share folder-files 'srv-adv' on the domain server 2008 r2.

In the share security I gave Barb, Bob, Brian and the administrator full control. That did not work. I received 'denied access' and 'you need permission to perform this action'.
However after I added and gave Everyone full control the three workers in advertising were able to access the shared folders and files. I thought by given just the advertising workers full permission that would have been sufficient. Not so, I had to add Everyone with full permissions.

I then created an 'advertising' group and added to that group Administrator, Barb, Bob, Brian and gave them full permissions.

I am stuck at this point. Do I remove from the share 'srv-adv' each user and then add the group 'advertising' to the share? What I want to do is to have the users added to advertising group unfettered access to the share 'srv-adv'.

And because I encountered 'denied access' and 'you need permission to perform this action' what "member of" do I add to advertising group without having to add 'Everyone' with full permissions?

PS I created only the group 'advertising' and did not create a 'group policy'. I don't know is that makes a difference.

Thanks

Go through Setup Shared Folder in Windows Server 2012 to see if sharing is setup properly.

However, check whether these users/group has sufficient NTFS permissions too (security tab)

This reflects a great article on Server 2012 / however what I am working with is Microsoft Server 2008 R2 - thus these new features are lacking. Thanks!