This exercise is from the Core Skills section on Fingertapping.
You will have seen this being played in the introduction video at the beginning of this section. It is a typical fingertapping lick, and a great practice exercise.
Hold the notes with your 1st and 4th fingers (as shown in the ActionTab) with your fretboard hand. The 'Prepare Note' symbol X is in those dots. Then Tap the 12th fret and as soon as you release your finger from the tap, it will sound out the note being held behind - the note being held by your 4th finger (yellow dot). Notice the X in the yellow dot changes to a P. That means you should instantly pull off that note with your 4th finger the moment it is sounded. Doing so will in turn sound out the note behind - which is being held by your first finger (red dot).
Now as you return to tap the 12th fret again, bring your 4th finger back again at exactly the same time, to the same fret and that means it will be in place for repeating the instant pull off again once you have tapped the string. Rinse and Repeat.
If you are confused, go over the introduction video again where we show this very exercise being done, and explain more about it.
You may have recognised that this exercise gives us a fast repeating triplet - 3 notes being played in rapid succession.
The notes are: E (12th Fret) C (8th fret) A (5th fret).
These 3 notes are the core notes of an A minor chord, so you'll find that this particular lick will work well in a solo played over that chord!
As always, when practicing get the technique right at a moderate speed (without gaps) before stepping on the gas!