If you aren't familiar with playing percussion on the acoustic, be sure to learn this at a very slow pace. Watch the videos very closely and pay attention to my hand movements. At first, it might seem like there's a lot going on with all the different motions, but if you learn it note-by-note it shouldn't be too overwhelming. Just go slowly and only advance to the next group of notes when you're ready.
In Part 1, we'll be using our picking hand to knock the guitar body as well as using the thumb to slap the Low E string. It might take some practice to get the E string sounding properly when you slap it, but keep practicing until you find that sweet spot on the side of your thumb's knuckle.
Tablature Reference
L.str = use left hand to slap the strings
L. bod = use left hand to knock the guitar body
R.str = use right hand to slap the strings
R. bod = use right hand to knock the guitar body
T = pluck with thumb
T Slap = slap string with thumb
M = pluck with middle finger
A = pluck with ring finger
Got it down? On to Part 2!