If it's a Hikvision IP camera directly connected to a Hikvision NVR on one of the PoE ports - you set the intrusion detection recording on the NVR. The NVR will setup the camera accordingly using plug and play. I'd first switch on the intrusion detection, set the area, schedule and actions in the NVR and apply. Then login to to the camera webpage directly and set the minimum, maximum object sizes only there (as these options are missing in the NVR interface) as this will keep the false alerts to a minimum.