Here's the USF CS support site on how to do it: http://cs.usfca.edu/support.shtml#login
Basically, perform the following steps:
1. Download Putty. This is a program that lets you access a Linux machine from a Windows machine. Look under binaries and click on the link labeled 'putty.exe'.
2. After installing Putty, just click on its icon and a terminal window will open up. Enter "stargate.cs.usfca.edu" as the host name and make sure SSH is selected. This will get you on to the stargate machine at school. Please do not work on that machine. Instead, ssh to one of the lab machines, as described next.
3. The lab machines are named something like 'hrn23511.cs.usfca.edu', where 'hrn' means Harney, 235 is the lab room number, and 11 is the machine number. To get on to that machine, you can enter:
% ssh hrn23511.cs.usfca.edu
You can also check what machines are available by entering:
% rusers -a
This will also tell you who is working on what machine.