Permission Rights

Hi all,

Not sure if this is the correct place to post this, as what I'm about to ask is actually a server-related question; server 2012R2. Reason why I'm posting here is because Windows8 is similiar to server2012.

So my question is this.

Folder A
Subfolders
Files

I have a file server and some permission settings to be put in place. Folder A and subfolders are read-only access to all, and I have put in authorized permission groups to access the various subfolders. However, I want the authorized permission groups to be able to have modify permissions on files, or whatever that is beyond the subfolders.

Currently my settings is as follows;

Root drive - shared to domain users, permission group
Folder A - This folder and subfolders; read only
subfolders - (inherited) folder and subfolders read only
Files - read, write, execute

When I open files such as powerpoint, I am not able to save/make changes. It prompts me "access denied. Contact your administrator."

Appreciate any advice in advance. Thanks!