The coffee percolator looks similar to a tea pot but works differently. Inside the percolator a bottom chamber holds the water, a tube leads out of the water chamber into the a perforated chamber where the coffee grounds are placed. When the water boils it travels up the tube, over the grounds then back down to the water chamber to get re-heated. The practice of using a percolator to make coffee is not ideal. This method of coffee brewing is discouraged by many, read why that is below, as well as some advice for if you do have to use a percolator to brew your coffee.
Coffee in a percolator is inevitably boiled several times over, leading to significant over extraction and the tarry bitterness which boiling produces. If you HAVE to use a percolator, choose a coffee which is low in acidity and VERY smooth, and grind it even coarser than for the French press. Allow it to perk for no more than 3 minutes.
SRC: For Step by Step directions for using a percolator to brew your coffee visit: www.howtobrewcoffee.com/percolator.htm