FAN 12v On/off Control by android application

Hi guys can someone help im planning to do a project a 12vfan control by android app just On/Off controll can someone teach me or help i already have bluetooth module 12v relay i dont understand what to do next Can somebody give me diagram or codes what to do a student trying to do expirement here tnx

Use 5V Relay, Power the Coil of the relay using a digital pin.