Pull long end of the movable lever to horizontal position.
Push the door brace down against the door.
Rotate latch if you want to secure the door brace against the door. (Optional)
Once the door brace is depressed and the lever is in horizontal position, pull up the door till it touches the ceiling of the cage. Check if the short end of the lever is under the door, make sure it does.
If you choose to do Step 4, rotate latch to release door brace.
Position long end of the lever on inside of trigger rod and release the door carefully. Trap is now set and ready to use.
* Note: If the trap is too sensitive, file a flat on both the lever and the trigger rod where they meet.