Yes Osodel, it's a bit disturbing to hear a D7 on a Cmaj harmonized scale. But as Eblue told us, he plays in a key of Gmaj, but he began by the 4th chord which is the Cmaj. It's not really didactic, the demo would have been more clear by begining with Gmaj.
He forgot to say the end of the verse with D/F/C and return on the F to finish.
The intro sounds better with this fingering : XX0560 and D (XX0232)
The rest is clear
Thanks Raskali