My Book Live - sub folder

Hi - I’m new here so be gentle - have done a quick search but not found answers . 

Ive installed a 3tb My Book Live - to be used as a “shared drive” 

I have created users and Shares - all ok - but I copied a folder from my hard drive to the shared folder - ie creating a sub folder - and it will not allow other users - WHO have full access ( private ) to open - It says they do not have access rights . 

Surely there is a way to approve this - 

I want to have Main share File - and sub folders under for various work flows - 

Any help welcome 

what mac os are you running?  I’ve heard of issues with lion doing this when copying folders to a share on the mbl.  I would delete the folder, created another sub-folder in the share and copy the files into that folder and see if it works.