When you first arrive, your primary supervisor will take you on a tour round the department, meeting people and doing various bits of admin along the way. Here's a guide to what will happen. Not necessarily in this order!
If any of these things don't happen, politely remind your supervisor!
1. Your supervisor should already have arranged a desk and a machine for you, in one of the postgrad labs. If this doesn't happen, it'll happen now. When you arrive, your supervisor will show you your desk, and you'll meet the other students in the lab.
2. Your supervisor will take you to meet the postgrad coordinator. You have probably already corresponded with the postgrad coordinator when you were applying to the department. The postgrad coordinator will tell you about the page you're currently reading! And say a little about the 6-month report and (for PhD students) the system of progress meetings. International students will also be given some information about visa issues. He/she will tell you how to get a student ID card, and deal with any enrolment issues that are still outstanding.
3. Your supervisor will take you to meet the office staff. They will give you a key to your lab (on receipt of a $5 deposit which is returned when you give the key back at the end of study), and organise swipe card access to the building (the Owheo building) once you have your id card.
4. Your supervisor will take you to meet the technical staff. The technical staff will set up your CS account, explain how to access e-mail, gitlab, and so on. The staff will also add you to the postgraduates e-mail group and any relevant lab or research specific mailing lists.
If you have general computer support enquiries in the department, you should email email@example.com.
5. Your supervisor will take you to see the department's website maintainer, who will add you to the department's current postgrad students web page.
6. Your supervisor will take you to meet the Head of Department, just to say hello.
7. Your supervisor will then arrange for one of the current students in your lab to take you to meet the other postgrads and lecturers in the department.