Alright so here's the deal...
You need to cool your lights.... AND you need to ventilate your grow room. You can do this with one vent/ fan system or two...
Advantages to one system: ease, one exhuast hole (in door/ ceiling), one fan.
Adv to two systems: better control of both, powerful fan for lights does not need to blow through carbon filter.
Using different systems is better if possible.
So, on the left in the pic are two systems. There is a fan sucking 'cool air' from your bedroom or whatever, blowing directly onto your light then directly out the room. There is also a fan that sucks cool air and blows it strait into the room, to be vented at the top.
On the right there is one fan, that sucks air though the light... the air sucking through the light will suck cool air from a hole at the bottom of your grow room, draw it over the light and take the hot air and push it out the room.
The blue things are where the carbon filter needs to be... it has to be at the 'end' of the grow room system. This is the air that will stink and you want to filter it before it leaves the room, not coming in.
You always want to suck cool air from as low as possible... and want to vent/ exhaust/ collect it as high as possible. It's that whole heat rises thing.
Another thing is passive holes you have made for intake/ exhaust have to be fitted with some sort of light blocker, to keep the light in, and also keep light out for the 12 hours of darkness each night of flowering.
Let me know if anything is unclear... or you have more questions.