The B flat minor chord is a 3-note chord consisting of the notes Bb, Db and F.
You can see these notes highlighted in the interactive piano chart below.
The chord itself is often abbreviated as Bbm.
Chords that are a superset of Bbm. The chords include more notes but always Bb, Db and F.
Chords that are a subset of Bbm. These contain less notes but all of them are included in Bbm.
In case you prefer a non-interactive variant of the chord chart, we've embedded a PNG image below that shows the notes for the the Bbm chord. Feel free to save or share the image as needed.