Hi, I work at a printing company as electronic prepress tech.
I don't understand how everything is networked. We're on a hub; 9 office PCs; in prepress we have 3 PCs (one a server) and 2 Macs. All computer have internet access.
Right now we use an IT company and they do much remotely.

Here's what I'm looking for, hope you can help with some if not all.
1) Basic configuration with a diagram or explanation on how its all connected.
2) How its all addressed (I don't understand the different ways; Workgroup etc.)
I thought it was IP addresses like a Mac network but the IT company has some on workgroup and something else?
3) FTP connection: They setup an FTP connection remotely to one of our PCs, one general folder for all clients. How can I setup a secure folder for a client.
4) Don't understand security software; we don't use it for the Macs.