All odd-size baggage must first be registered at your airline's counter, after which you will drop it off at Odd Size in either Terminal 2 or Terminal 3.
If you are flying with a SAS-handled airline, all odd-size baggage must be dropped off at Odd Size in Terminal 3. In all other cases, odd-size baggage should be dropped off at Odd Size in Terminal 2.
You can find out which terminal your flight checks in at by searching for your specific departure via this link.