With the Catchmaster Disposable Fly Trap, you will just add water and the attractant inside of the bag. Be sure to hang the trap at at least 10-30 feet away from the area you are wanting to protect. It will lure the flies inside of the bag, and they will not be able to escape. This is how they die. If the solution in the trap falls below the marked water line, add more water.
The Catchmaster Disposable Fly Trap (975-8) will typically last 4-6 weeks.