Ab maj7
The Ab maj7 chord consists of the Ab (Perfect unison), C (Major third), Eb (Perfect fifth) and G (Major seventh) notes.

How to play the Ab maj7 chord
- Find Ab (Root) on the piano keyboard
- Add C (Major third) — 4 semitones above Ab
- Add Eb (Perfect fifth) — 7 semitones above Ab
- Add G (Major seventh) — 11 semitones above Ab
- Press all 4 notes simultaneously to sound the Ab maj7 chord