Serving coffee to a large group becomes much simpler when you have a large coffee maker that brews big batches all at once. Most of the larger urns, for 60 cups or more, work on a percolator method of brewing, which can take some time. For long events where the coffee is expected to flow without end, consider keeping a smaller pot going for quick resupply when necessary. Read the manufacturer's instructions regarding the setup involved with your particular machine before getting started.
Remove the filter basket, stem the basket fits on to, and fill the urn up with cold water to the 60-cup mark. Lines are typically etched on the inside of the urn to indicate the water level for various gradations.
Replace the filter basket into the urn and put a coffee filter into the filter basket. Fill with three to four cups of ground coffee for 60 cups of coffee. The user manual of your percolator may offer specific recommendations for amounts. If grinding your own coffee beans, choose the "percolator" or a "medium coarse grind" setting on the grinder for best results.
Fit the lid onto the machine and turn on the percolator. These machines can take up to 30 minutes to complete their cycle, so make sure to get started with this process well before the guests begin to arrive.
Look for a light indicator that shows when the cycle is complete. Some machines display a light when the coffee is ready, while others have a light that turns off when its cycle is over.