In the lesson, students learned about writing long and short notes in music, as well as high and low notes. They discussed the importance of time signatures, which consist of two numbers at the beginning of a piece of music, indicating how music is grouped into measures. The group explored how music is organized in bars, and they practiced counting beats, specifically using examples like “Mary Had a Little Lamb” and “Amazing Grace.” This grouping helps in understanding rhythm and improves their overall performance when playing music.