In Big Nate's locker. The comic strip when completed gives you the combination 9305. (you can't use this until you finish assembling the comic strip) (see related question)
in the cabinet on big Nate island
In Nate's locker. The combination is on the assembled comic strip.
It is in the secret store room behind the filing cabinet in the detention room on Big Nate Island. You need the blue prints from Nate's locker in order to access the secret room.
you climb up the rope
The clapper.
You have to get in detension
in the detention room
you use the stink bomb wow
It it in the secret passage in the detention room on Big Nate Island.
get the bell clapper
In the file cabinet, in detention, in the school.
pull the power switch on