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. This clef indicates the position of the note G.
The head of a note indicates its position, on the staff, e.g.:
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.