To make it easier to wind the film on, stick something into the top of the empty spool. Here I used the ring pull from the can,
As you wind the film on, the film in the take up spool will tend to keep springing back. To keep some tension on the take up spool, place a little tissue paper on the base of the take up spool and tape over it. Don't make this too tight or it will be difficult to wind the film on.
That's it! The completed camera is now ready to used. Make sure the shutter is closed. To wind the film on, turn the winder on the empty take up spool anticlockwise. Listen for the clicks. Count 6 clicks for each photo if using a 24mm square frame, 8 clicks if using a 36 x 24mm frame. DO NOT try to wind the film back into the other canister with the clciker in place - the clciker will probably tear the film.