Bb aug/C
The Bb aug chord consists of the Bb (Perfect unison), D (Major third) and F# (Minor sixth) notes, with C as the bass note.

How to play the Bb aug/C chord
- Play C as the lowest bass note in the left hand
- Find Bb (Root) on the piano keyboard
- Add D (Major third) — 4 semitones above Bb
- Add F# (Minor sixth) — 8 semitones above Bb
- Press all 4 notes simultaneously to sound the Bb aug/C chord