Create a musical staff with five lines. There will be four spaces between the lines when you are finished.
Write a note that rests directly on the top of the staff. Don't use a ledger line for this note. This note is a G.
Draw a ledger line above the staff, it should be just slightly longer than a note-head. Use the same spacing you used for the permanent spaces between the staff. Generally this is about four millimeters. Draw a note directly on the ledger line so that the ledger line splits the note. This note is A.
Create another ledger line in the same horizontal position as the first ledger line. This time, place a note so that it rests on top of the ledger line. This note is B. Continue adding ledger lines and extending the staff upwards until you get the note you want.