F m6/C#
The F m6 chord consists of the F (Perfect unison), G# (Minor third), C (Perfect fifth) and D (Major sixth) notes, with C# as the bass note.

How to play the F m6/C# chord
- Play C# as the lowest bass note in the left hand
- Find F (Root) on the piano keyboard
- Add G# (Minor third) — 3 semitones above F
- Add C (Perfect fifth) — 7 semitones above F
- Add D (Major sixth) — 9 semitones above F
- Press all 5 notes simultaneously to sound the F m6/C# chord