This is the rhythm guitar part I played of the full tempo version on the BYCU Backing Tracks CD.

You can see that I used a simple Bb7 for the I chord, and an Eb9 and F9 for the IV and V chords respectively. The final I chord is a Bb9, played up in the 13th position.

You can use this rhythm, with slight variations in the timing, and even using different chord voicings, over and over, for a funky feel.

Notice in the score:
* The dynamic markings - "p" and "mf" which mean piano (quiet) and mezzo forte (medium loud). In this tune, you strum lightly on the first beat of the measure, almost inaudibly. Then you strum harder for the reat of the measure, creating accents. Only the first line is marked. You'll see the word "simile..." in measure 3. That means to continue the same for the rest of the tune unless indicated. You play all but the last measure that way. Listen to the CD if you have it.
* After the first strum, you chop the rest of the chord strums, giving a funky, syncopated and rhythmic feel.

Start as slowly as you need to in order to be able to play cleanly and steadily.

Have fun!
JG