Modeling - The teacher will draw the five parallel liines on the board explaining that in music this is called a "staff" and that musical notes have names and are written on a staff.
She can then proceed to assign the names to the lines: e g b d f.
She can then proceed to draw a G clef on the staff explaining to the students how she is doing that - especially that the G clef ends on the line named "G" which is why it is called a G clef.
Then I would suggest that she hand out staff paper to each student so that they can practice drawing their own G clefs. She should walk around the room checking papers to make sure the students have the right idea. Staff Paper can be downloaded from the internet or from Word.
Next would be to explain what a signature is and draw in the time value of 4 4.
Explain that the top number means that there are four beats in a measure. Now probably your students are wondering what a measure is. This would be a good time to explain by modeling first on the board that a measure is the space between two bar lines at which time you can write on the board two bar lines labeling them and the explaining the measure.
Then you can have ur students do the same and walk around to make sure there is adequate space on their papers to form a measure. Next if you keep a word wall in your room, I would add the words, G Clef, staff, bar line and measure. You may have the students repeat the words as a group as u point to them.