Watch the Boba Funk: 2 online guitar lesson by Ben Lacy from Two-Hand Groove Guitar
I'll show you that bassline nice and slow here and to keep it simple I'll just use my left hand thumb. This line is a kind of mixture of mixolydian and pentatonic, with major and minor 3rds and classic chromatic runs.
Start with D-E (frets 5-7) on the A string, then slide G-G# (5-6) on the D string. Back to D-E on the A string, then slide low G-G# (3-4) on the E string. Next the classic chromatic pickup frets 4-5-6-7 E string, 4-5-6-7 A string, then 9-10-11 (still on the A string). On the repeats I leave off that first D, so it's just E then G-G# and so on.
Count along with me if you find the rhythm tricky at first.