To set your default printer, you will need to be logged in as yourself, IT cannot do this for you.
Once you're logged in, click on the windows button in the bottom left of your taskbar and begin to type printers:
Once you see your printers and scanners, click on it in the right pane.
Then you need to check to see if Windows is managing your printers, we DON'T want that. If Windows is managing your printer, it will retain your most recently used printer each time. Turn off the option for Windows to manage the printers, ensure the checkbox circled below is NOT checked:
Then go to the printer you would like to be your default, in your list of printers above.
Click on the printer you want to be your default and choose manage:
From here, you can designate the printer to be your default:
Once you've done this process, the printer you have chosen to be your default should remain the default until you change it again. You can still choose other printers, if you wish to use a different one, but it will default back to the chosen printer. This process must be done for each user on the computer.