In order to get the keys to your room you first have to sign your contract. You do this when you arrive in Karlstad.
You can't have your keys before the starting day of your contract which is January 8th 2019. You must also have paid your rent to get your keys, you find more information on how to pay your rent here.
When you arrive in Karlstad you have to visit the caretakers' office at Campus and there you will get to sign your contract and then get your keys.
The first day to sign your contract and get your keys is January 8th 2019. Opening hours for the office is workdays 1pm-3pm. Between January 14th and January 25th the office is also open 10am-12am.
Here you can find the address and contact information to the caretakers' office.