The Abmaj7 can be played in two ways but both are difficult. We use the index finger to barre the first fret across all the strings. Leave the top joint of the finger slightly hanging over top. Next the ring ringer barres the C, E, and A strings at the third fret, it can make for an awkward stretch. Otherwise, we can place our middle finger on the third fret of the C string and the ring finger on the third fret of the E string. And finally, the pinky is placed on the third fret of the A string. It will be hard to cram all three fingers in, for most people the first method works best.