Most of the time, you will be using both hands while finger tapping. When playing tapping passages, you'll usually either be hammering on from your fret-hand to your tapping-hand, or pulling off from your tapping-hand to your fret-hand.
In this exercise, we will be ascending and descending on the strings. While ascending, your fret-hand index finger will hammer on the 9th frets, then your tapping-hand index finger will hammer on the 12th frets. You will repeat this on all 6 strings. While descending, your tapping-hand index finger will hammer on the 12th frets, then pull off to your fret-hand index finger on the 9th frets.
Take it very slowly while you get use to the motions. Also, make sure every note is equal in volume.