This piece starts with a walking bass line in E that slides into an E13 chord on the top three strings. Typically these walking bass lines are palm muted (though I didn't in this performance example). Take note of the interplay between the E13th chord over the I (major sound) and the A7 chord over the IV (dominant sound), which Fats used a lot in his playing.
Also take note of the V to #V turnaround, another characteristic Fats-ism. The turnaround in the 11th and 12th measures features some nice two note voicings on the A & G strings. Be sure to use your middle and index fingers to dampen the other strings so you can strum the whole guitar (fatter sound—no pun intended!).