You are welcome to visit the First curator at office hours Mon: 15-17, Tues: 10-12, Wed: 15-17, Thur: 16-18. He will help you and answer all your questions about the nation. The fee is 255 SEK/semester and all you have to bring is your ID, your letter of admittance and your P-number.
Can't wait to join? Log in to Uppsalastudent.com and register immediately! After that you are welcome to come by the nation and pick up a temporary card until the physical one arrives in your mailbox.