The aerator is the screen on the faucet. Generally the last half-inch or so of the faucet unscrews. Turn the water off, then unscrew the aerator. You may get some gunky water coming out, but with the pump off there won't be much pressure there. After the aerator is off, turn the water on and see what happens. You may find yourself transferring the gunk from the faucet to the drain trap, but at least you will have water coming into the sink.
Generally, you will find an aerator on both the kitchen and bathroom sinks. Shower heads and tub faucets generally don't have them. Sometimes you may have to use more than finger strength to loosen the aerator. I generally wrap it with electrical tape just because I have plenty of that here and then use a pliers. It won't take much effort to break the aerator loose. As I said, often you can just use finger strength to do it.
Enjoy your new coach!
David Lininger, kb0zke
Heartland mpg 181 (sold)
1993 Foretravel U300 (for sale)