Originally Posted by: emerrryweather

I am trying to work out how to find the notes of a song ( i.e. the notes the singer uses ),

[p]That's exactly what sheet music is for. :) It shows you which notes to play & when to play them.

Doing it without reading the music requires aural skills, "ear training", which you develop by learning to identify relative pitches in a melody or musical passage. Knowing basic major & minor scales, some chords, the notes on the fretboard is all fundamental here.

Assuming you already know how to play & the guitar layout, I cover basic ear training for intervals in this tutorial.

https://www.guitartricks.com/tutorial.php?input=2401

Hope that helps!