The great composer and classical guitar teacher Fernando Sor was, and still is, one of the majors focal point of the study of the classical guitar. He wrote works of various kinds and of great harmonic richness, like the Sonatas, but also simple didactic works, such as the Opera 60, addressed to those who began playing the classical guitar. One very easy to study, for those who started playing the classical guitar is the No. 1 in C major. Try to look at the tutorial and listen to the recording before trying to play it.