This lesson is a powerful approach to bass playing. The concept is built on octaves. If you look at the music score / bass tab you'll see that the octaves occur at the end of each bar. Take a look at the fretting hand fingering shown under the bass tab for those octaves. You play those octave notes with your second and fourth finger. This whole exercise is based on the lesser used portion of your hand so you might find it difficult to get the strength that you need. It's those octaves which outline the chords for each bar.
The tonality of these chords comes from the pull-off notes that precede the octaves. Those are the 4th and 3rd scale notes, with the pull-off emphasising the 3rd scale note - indicating major chords. At the start of the bar is a 4th/8va combination of notes. This is where things can get a little bit experimental music wise. The two bars are identified as E Major and A major as shown. However, because that 4th/8va combination can also be interpreted as a power chord alternative chord ideas are shown above the chord boxes. Try both versions out.
For reference, the root note (based on the chord boxes) is the lowest note of the octave at the end of each bar. Bar 1, 7th Fret A-string, Bar 2, 5th Fret E-string. Notice that you sustain the high octave note through-out each bar - even while pulling off with other fingers!
If you move bar 1 directly up so that your octave begins on your E-string (7th fret B-string) you will be playing a B Major bass lick. Try substituting it for the A Major in bar 2. You'll probably find this easier than the lesson here. The reason why is that you are only adjusting strings, not moving up or down the fretboard at the same time. We thought we'd just give you the harder version first!