Watch the Route 103 online guitar lesson by David Hamburger from Essentials: Fingerstyle Blues
It would be worth taking a little time to just noodle around with the notes of the melody to connect the sounds - which should be relatively familar - with the fingerings, which may not be. Ultimately, the idea is to be able to keep an alternating thumb like this going and just improvise a bit with the pentatonic scale on top, and there’s no time like the present to start trying that out. In a sense, you could view this tune as just one example of how to coordinate some minor pentatonic licks over a G bass. Once you can play the tune as written, it’s time to start coming up with some variations of your own.