When you start up Netmeeting on your PC, select call - new call - then enter the IP address of the user you want to get to. This is necessary if you don't use a catalogue server, which you can do later if you like how netmeeting works. You can use it to transfer files as well. You must select the "use security" checkbox - I haven't made it work any other way. This means you must supply an admin user/password when connecting. I use the relevant domain admin account myself.
You are asking - how do I know the IP address of the end station I want to connect to? If you are using dhcp, you will need the user to tell you first. I have a batch file I drop on their desktop called my-ip.bat (or similar) and it goes a little like this-
ipconfig
pause.
So, you call the user and ask them to enable remote sharing (by right clicking the tray icon) then click the my-ip icon and read their address back to you. If your addresses are static, even easier. You then go into Netmeeting and selectCall - new call (with security) and that is it. I did see wierd locking problems at first where the scree would freeze on my end. Pulling up task manager via the keyboard then killing another non-relevant task(like an instance of explorer for instance) got my mouse back. SP2 has greatly improved the whole operation of it. For previous versions of windows you can download the latest v3.x of it for your other boxes. Win95 needs Explorer 5 (minimum) installed for it to work, like most of the new apps.
Hope this helps, there are articles on this site covering the same thing, but this is the cut-down version that works. After you do 1 or 2 you should be able to set up a client in about 5 minutes (or get the trainee to do them).
Bon Appetit (PS - the whole answer wouldn't fit in one response, in case your'e wondering.