Placethe other fingers for the chord in the right place, except your index (barring) finger. For Bb you would place your middle finger on the C string, second fret and your ring finger on the G string, third fret. Bar with index finger. Finally, place your index finger on the fret that needs to be barred. For Bb, this means placing your index
TheAmaj7 chord is rather easy and uses just two fingers! The index goes on the first fret of the G string and the middle finger plays the first fret of the C string. The biggest issue is making room for the two fingers, you may have to slightly move the index back to fit them both. And don't forget to also play the bottom two strings, they should have clear tones when plucked. AUyA.