Carefully insert the new aerator into the collar, making sure that the mesh end is facing downward. Push the aerator firmly into the collar to ensure a tight fit.

Place the aerator gasket on top of the aerator within the faucet collar. This will create a seal between the aerator and the faucet, preventing any water from leaking out.

Use your fingers to tighten the faucet collar and aerator onto the end of the faucet.

Make sure it is tightened securely, but not too tightly to avoid damaging the threads.