The Key of D Major
The tune is played in the key of D major which is given below. Practice going up and down the scale slowly to get a feel of the different spacings for your fingers on each string. The tune never uses any frets outside of this shape so it is worthwhile getting to know it fluently as it will aid playing the piece.
The tab below shows which frets on which strings to place your fingers.
Finger 1 will always play fret 2 of every string
Finger 2 will play fret 3 or 4
Finger 3 will play fret 5 or 6
Try to keep each finger held down after it has been played where ever possible. The video below should show where this is possible and should also give the rhythm.