B major/F##
The B major chord consists of the B (Perfect unison), D# (Major third) and F# (Perfect fifth) notes, with F## as the bass note.

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