D sus4/F#
The D sus4 chord consists of the D (Perfect unison), G (Perfect fourth) and A (Perfect fifth) notes, with F# as the bass note.

How to play the D sus4/F# chord
- Play F# as the lowest bass note in the left hand
- Find D (Root) on the piano keyboard
- Add G (Perfect fourth) — 5 semitones above D
- Add A (Perfect fifth) — 7 semitones above D
- Press all 4 notes simultaneously to sound the D sus4/F# chord