The musical alphabet consists of 7 letters:
Music is written on a staff, which consists of 5 parallel lines. Notes are written on these lines and in the spaces between them. The treble or 'G' Clef is placed at the beginning of each staff line. Guitar music notes are written on the treble staff. The head of a note indicates its position on the staff.
When the note head is below the middle staff line the stem points upward and when the head is above the middle line the stem points downward. A note placed on the middle line (B) can have its stem pointing either up or down.
Bar lines or measures divide the music into sections. A double bar line indicates either the end of the music, or the end of an important section.