How do I setup security in my shares

I recently received my ReadyNas 102 and have just finished configuring it via Raidar since I wanted to use both of my drives as independent volumes and I must confess it was easier than I thought it would be.

I currently have the default shares and all the computers at home are able to access it without any problems, I also created individual folders for each of my family members so that they can store their information. 

The problem is that all of the folders I have created can be accessed by everyone on the network and I would like to set the folders so that each person can only access their folder and not be able to access anyone else’s folder; of course, me as the admin will need to have access to everyone’s folder.

Also, I would like to stablish storage quotas to be able to keep the storage space under control.

Can someone please tell me how I can do all of this or if there is a document that explains how to do it please point me in the right direction.

Any help would be greatly appreciated.

Thanks