First, ITR will contact you to tell you that your PC is due for replacement, and schedule a time for the replacement.
Second, make sure your data is synchronized with OneDrive and make sure your browser data is backed up or otherwise synchronized.
Finally, At the scheduled time you will stop by dropped off your old computer and pick up the new computer. Which you will be able to finish the setup for, either on campus or off campus. After the short setup process the PC will be ready to use.