Whe you install the sofware put in your credentials as shown, or, if you get it wrong or need to check something, you can see them from System Preferences.
Password: what the ITs guys gave you
Some times you get your credentials in the form of an email address and password eg
so use those bits as your credentials. Sample screenshot above.
Now, click on the fan symbol on the menu bar, and select a hotspot. In the example below I use MOBILE which is Swisscom.
What should happen is that the iPass client should kick on and log you on. Sometimes this doesn't happen, so if it doesn't, go back to the airport fan, turn airport off, count to ten, and turn back on again.
UPDATE: Sometimes iPass doesn't connect at all and just seems to go to sleep. If this happens, you may need to quit the iPass application, and relaunch it. It doesn't have a 'quit' button, so what you can do is use Activity Monitor, click on iPass and press 'Quit Process'.
Then go to System Preferences, click on iPassConnect and it should re-launch.