This is easy, I help people map drives all day as a service desk tech. First get the EXACT drive path from some one that has the drive allready. You can do this from run and type //, this should bring up any network paths accessed, find the right one and write it down. IF the run line does not show what you need, go to a coworkers pc that does have the share mapped Right click my computer, map network drive and pick the correct drive letter. This will give you the adress You will need to type in on your computer in a moment. The adres should look like //server/ folder EXAMPLE  //ninj45/payroll.
Once you get your information, mambo over to yer box. I am assuming its windows 2000 or XP. Right click my computer, Left click map network drive. Pick the drive letter You want to assign the network share (S drive X drive any letter works)  on the second line type in that info you got from a colleqague //server/folder OR you can hit browse and find the new server, then navigate downward once you have selected the server you should see the items available to you hosted on that server. Click the folder you want, and click reconnect at logon. Click ok you should be good from that point on.  Way cool if this help, I just woke up and am writing this for someone assumingly semi familiar with a pc from your post I gathered you are,  ;)

IF all else faild call help desk or hollar at yer IT dude.
Good luck
Borgo