A m3/C
The A m3 chord consists of the A (Perfect unison) and C (Minor third) notes, with C as the bass note.

How to play the A m3/C chord
- Play C as the lowest bass note in the left hand
- Find A (Root) on the piano keyboard
- Add C (Minor third) — 3 semitones above A
- Press all 3 notes simultaneously to sound the A m3/C chord