Tune your guitar and make sure that the bridge and the neck are properly oriented. Use a tuner if you can purchase one, or tune it by ear.
Play an A-minor chord to start the song. As you are playing the chord muffle the chord a little by pressing your strumming hand slightly across the strings. Play this chord a few times in this way.
Move your hand to the lower E string and hammer on from a G to an A, or from the third fret to the fifth fret. Now take your pinky and play the a D on the A string or the fifth fret and slide this up to the seventh fret. Hold this for a moment then once again play the A on the fifth fret of the lower E string.
Return to the A minor chord after letting the A note ring out and start the progression again. Make sure to mute the strings ever so slightly as you play to give it the quiet feel it has in the original track.