Place it at the start of a scene, just before the door opens, then follow it with a door knock for the arrival and a bell ding once the visitor is seen. For a mystery reveal, put the dun dun dun sting after the door opens instead of another bell.
About this sound
This is a long, slow ring from an old mechanical doorbell, with a deep metallic tone that wobbles and fades rather than chiming cleanly. It feels nostalgic and a little eerie, like a sound from a quiet hallway in another century. Presented as a bell from 1904, it carries the unhurried character of a bell from that era.