The A major triad is made up of 3 notes from the A-major scale. The root, A, the 3rd note, C-sharp, and the 5th note, E. I'm gonna play for you a 2 octave A-major triad. Our first note is gonna be A, the open string. Now, C-sharp, the 4th fret on the A string. E, 2nd fret on the D string. And now, A, 7th fret on the D string. C sharp, 6th fret on the G, E, 9th fret on the G string. And now, A, the 14th fret on the G string. Here it is, up and down, in 2 octaves. And that's how to play the A major triad in 2 octaves on the bass guitar.