Posted 27 January 2011 - 07:11 AM
Without knowing the OS, it can vary. If you right-click on the folder you want to share, you should see a tab called Sharing. In that tab, you can browse to share properties (sometimes under Advanced Settings or some such,) where the default is Everyone having the Read right checked, and nothing else. Sometimes, it is under "Permissions." You would then add other users. If they are local to that machine, then you would just browse that machine. If they are on other computers, you would need to browse to those computers by hitting the Location button and select the machine(s) from which you want to add users. Again, depending on the OS, you may or may not see other machines.
Be careful about removing the Everyone group. You should make certain that the local user whose folder it is has Full Control, as well as the administrative account on the computer before you touch Everyone. Do NOT give Everyone ANY "deny" rights. Read and Change is good enough for all the other users.
If you have Pro, Professional or Business, then you can set up NTFS shares, which are more granular and a better route, but also more complicated. In that case, you would leave the Share properties alone, and administer it entirely through NTFS properties.
An easier alternative that has a lot of upside is a NAS with RAID 1 (mirrored drives.) It is always available, and has it's own security. The mirrored drives provide protection in case a hard drive fails, and you have a central point to manage (as opposed to running all over various machines and setting up individual circular shares.)