This exercise is from the Core Skills section on Pull Offs.

This is a little solo trick which employs a sequence of notes played using mostly pull offs. The notes are played in 'triplets'. This means rapidly playing 3 notes in sequence, and in terms of music score - a triplet equals one beat in a measure. Listen to the ActionTab to identify what triplets sound like, and how to play them. Triplets are often played using pull offs, but not always.

The notes are from a B natural minor scale on the High E string. The notes are D, C#, B (repeat). The reason we are playing high up the frets here is partially to accustom your little finger to pull offs. Usually this is the finger needing the most work when practicing guitar. Especially when it comes to pull offs.

When you can play this triplet pattern even at a moderate pace try doing it on other strings and lower down the fretboard. This is more difficult for your fingers and will help you improve this technique, and your finger strength.

Don't worry if you can't play at the same pace as the normal speed version. Keep practicing and it will come. As long as you can play the triplet consistently and clearly, move along to the next exercise and see how the technique can be developed upon.