If you have a grill with the burners running front to back, you will need to use one of the burners on either end. Lets say you are using the left most burner. This means you will place your smoke bombs directly over this burner (and under the cooking grate). The ribs will be placed as close to the right side as possible. If the rack is short enough to be placed running parallel to the burners, set it as far to the right as you can get it. Otherwise, you might have to place it in a more diagonal position on the grill.
Place the rack, bone side down on the grill, close the lid, and adjust the grill until it holds a temperature of 300 degrees F. Now, let the ribs cook for 30 minutes. Don't open the lid. This will hold in as much smoke as possible. Don't expect a lot of smoke to billow out of the grill as there won't be a tremendous amount of smoke production.