fingerprint noticed by USCIS

My I-485 was received on Sept.20, and just got the notic for scheduled biometrics (code3) appointment via mail from USCIS and mentioned you need to bring the notice letter to the appointment. But my I-485 receipt did not state to schedule biometrics yourself by calling. In fact, it did not mention biometrics at all. I guess you can call as they said to make an appointment and wait to receive the letter with your scheduled appointment. I might be wrong though. Good luck.