You must change your address at the post office when you move to or from your student accommodation. The post office will need your name, street, floor and room number. Writing your name on the mail box is not enough to receive your mail, you have to notify the post office with the correct details of you new address. That is you have to go to a post office and fill out a form to register your address. 

If you are to receive a parcel that cannot fit into your mail box you will receive a notification, either in your mail box or electronically, about where to pick it up. It is usually at the post office closest to your accommodation.

If you receive a parcel addressed to the previous tenant, you should hand it in to the post office.