Clean your grill, prepare your food and setup your grill for Indirect heat, meaning the burners are only ON on one side of the grill, likely on a medium-low setting.
Bring your grill's internal temperature up to between 225°F and 300°F depending on what you are planning to cook. Adjust your burners to maintain your chosen temperature.
Fill your smoker box with your smoking wood chips of choice...do NOT soak them in water...and close the lid.
Place the smoker box over the lit burners until it starts to smoke. If the chips ignite, blow out the fire, add more chips to the box if necessary, and move the smoker box further away from the direct heat.
Place your food to be smoked on the opposite side of the grill and close the lid.
Add wood chips to the smoker box as necessary every 30 minutes or so depending on how much smoke flavor you wish to add.
After adding smoke, continue to cook your food over indirect or direct heat until it is up to a safe internal temperature and remove from the grill.
Using BBQ tongs, place your smoker box on the warming rack of your gas grill until it has completely cooled down before disposing of the charred wood chips.