Set up a fan behind the curtains on each side of the stage.
Place a large pot on the ground near the fan. This is where you will put the dry ice.
Add five to 10 pounds of dry ice for each 15-minute period of use into the pots. Add four to eight gallons of hot water. In small rooms you will need two pots and 15 to 30 pounds of dry ice for use of up to an hour. For large rooms you will need three to four pots of hot water and up to 50 pounds of dry ice for fog, lasting up to an hour.
Turn on the fan after adding the dry ice to the hot water mixture. Blow the air in the direction of the stage.