Percolation is the original method for making coffee. Inside the brewer, there is a chamber to hold the grounds and a tube that connects that chamber to water at the bottom of the unit. When placed over a heat source, water rises in the tube and trickles through the grounds to create coffee. This is a difficult method to master because over extraction and re-brewing will create bitter or tasteless coffee.
A simpler, more common method for making coffee is called drip brewing. For this method, coffee grounds are placed in a filter, a heating element heats up stored water which then passes through the grounds and into a pot or server. This is pretty much a fool-proof method for making coffee and several makers are available that can brew a single pot or two pots at once.