The major 7th chord uses four notes that come from the major scale. In this case, we're gonna play "G". So the G-Major 7th chord is "G", "B", "D" and F-Sharp. Those notes are the root, the 3rd, the 5th and the 7th scale tones. So even though we're only playing four notes, we still call them root, 3rd, 5th and 7th. So now we can practice two octaves of the G-Major 7th chord. And that's how you play a major 7th chord on the bass guitar.