Hey Growmie,
The easiest and cheapest way to set-up an air-cooled grow light reflector and carbon filter is to hang the filter before your hood and connect the two using a short piece of flexible ducting. Attach your inline fan on the other side of the reflector and vent the hot air directly out of your room (or tent) using more ducting. For best results, keep this path as short and straight as possible. Kinks will restrict airflow and the exhaust/ cooling system will become less efficient the longer the hot air has to travel. Also, keep enough slack in the ductwork to allow for your lights to be raised and lowered. To get rid of the potentially smelly air inside your garden, attach a separate inline fan to a flange kit on top of your carbon filter. Make sure that the fan and filter are large enough for your growing space and vent this air outside your room using flexible ducting. Hopefully, this was helpful, and remember ..." Happy Growing" and "Free your mind one puff at a time".