In order to get the police clearance certifcate, you need to follow three steps:

1) Prepare a power of attorney saying the you want to ask someone else to do this it for you. You need to sign the power of attorney, then press a fingerprint on the signature, and then scan the document and send it to your friend. 

2) You need to hold this power of attorney, then take a photo, to prove that it is your entrustment. Then send the photo to your friend. You friend need to print it clearly. 

3) You need to send the front page of your passport and the visa page in China to your friend for him to print.

After preparing these documents, your friend needs to take these documents to the west gate of the Exit Entry Hall, No. 357, Middle Changjiang Road (长江中路357号, 户政与出入境大厅). In addition, if your friend is an international student of the school, he needs to bring his own passport and study proof. then he can get the certifiacte to prove that you didn't have criminal records during your stay in Qingdao in China). This process may take 1-2 days.