Start with a clean charcoal grill. Remove the cooking grate and start the charcoal. I'm using a charcoal chimney which will light the perfect amount of charcoal. You will need enough charcoal to cover half the coal grate, about three layers thick (that's three layers of charcoal).
Once the charcoal is lit, place one of the aluminum pans on the coal grate and pour the charcoal on the other side. I bend the aluminum pan to fit the grill shape to make it easier to work with.
Now, it's time add the wood. The wood is important for creating the smoke. I suggest large wood chunks since it will take longer to burn and provides smoke as you need it. Use several chunks for a good smoke supply.
Return the cooking grate and place the second aluminum pan on it, directly over the charcoal. Fill with as much water as it can hold. The goal is to keep the grill at a temperature just above the boiling point of water (around 225 degrees F.) The water will steam away slowly and you shouldn't need to add more water, but keep an eye on it.
Now you have converted your grill into a smoker.