You can buy the theory book in regular bookshops, and you have to read and learn the theory by yourself. There are tests on the internet that you can use for practice ( or If you have any questions regarding the theory you may of course ask your teacher during the driving session. There is no need to book an appointment to take the theoretical exam; you can show up at the nearest traffic station during the opening hours. Passed theoretical exam is valid for 3 years. The test costs 600NOK. If you fail the test you have to wait 2 weeks to be able to take the test again. You can find more information at Norwegian Public Roads Administration: