Most sink faucets will include an aerator. An aerator will mix air with the outpouring water and will reduce any splattering that could happen without one. It also saves on your consumption of water since glasses and pots will fill up faster.
The first thing you should do is turn off your water to avoid causing a mess. Do this by shutting off the valve under the sink. Before you do this, you should fill a small bucket with water that you can use for rinsing later.
If you are replacing an aerator, you will need to remove the old one by unscrewing it. This can usually be done with your fingers, but you can also use a wrench, being careful to not hurt your faucet by using a towel between the tool and the unit.
Take the aerator completely off the faucet, making sure you take note of how it was assembled.
Rinsing the Parts You Intend to Reuse
If you plan to clean your current aerator and reuse it, rinse out any debris from the screen of the aerator. Doing this step will allow water to flow through your faucet easier and the flow will no longer be reduced. You may want to clean other parts as well.
If you are planning to install a new aerator, make sure that you have all the pieces you need.
Once all the parts are cleaned, you will want to reassemble them in the reverse order they were removed. Once all the pieces are in place, you should be able to tighten the aerator with your fingers.
Once you have finished, you can turn your water back on and experience a better flow of water.