This is based on "Danza" by Aaron Shearer from " Classical Guitar Technique Volume 2". The video is a straight rendition of Danza, plus an extra variation. Strictly speaking, this should really be called something like "Variations on a theme by Aaron Shearer". But that's boring so I gave it a new name.
I taught myself to read music and the basics of classical guitar with Aaron Shearer' from "Classical Guitar Technique Volume 1", which was first published in 1937. This has consistently been one of the most popular classical guitar methods ever written. A new guitar method by Aaron Shearer, " Learning the Classic Guitar", is published by Mel Bay and is widely available.