Chinese door locks often work differently from the one you know in Europe. Make sure that you and all other tenants ask the landlord how to operate the keys and lock and have him/her show it to you when you move in. If you lock yourself in, call the landlord to come or send someone. Call the office if you need help with communication.
If you lock yourself out and neither the other tenants has a spare key, then please contact the landlord to open the door for you (if the locks need to be replaced you will have to pay the costs, appr. RMB 300)