Usually the keys can be picked up from maintenance services when the agreement has been signed. The key pick up date is agreed on at the time of agreement signing. You must have your ID with you when you pick up your keys.
When moving into a new first time apartment, you get your keys at a special tenant meeting.
Do you have problems in your apartment?
If your apartment hasn´t been cleaned well when you move in, contact the property manager. If this happens during after the office is closed, take some photos of the condition of the apartment before cleaning. Take care of the issue with the management during the next work day.
The tenants are responsible for all possible problems if they agree on changes outside the agreement framework. Then the landlord cannot take responsibility on the quality of the cleaning when turning in the keys, the condition of the used, sold or stuff given by someone, or of the after-service or of payments made between customers.
For small, not for sudden problems, you can fill out an online service advice.