Here are documents which explain the notes on the neck.
Click on the image to download the PDF.
E, F and G.
B, C and D with the song Go Tell Aunt Rhody.
The notes G and A with the Alphabet Song.
The notes D, E and F with the Snake Charmer song.
The notes A, B and C with a Russian Folk song.
The notes E, F and G with Yankee Doodle as a duet.