Carbon filters are attached in grow tents - every grow tent needs to have a minimum of one such filter. These filters are generally attached to the ceiling of the tent. These filters don’t really hang around in isolation but are connected to exhaust fans and ductings. The air goes into the ductings via the filter and out of the tent via the exhaust, which is connected on the other end of the duct. Try and place the filter as high-up in your grow tent as possible. If there are any openings or gaps make sure you use a duct tape to close them.