When growing, How do u stop a room smelling?

Is it a carbon filter? and where would I accuire 1 of these devices pls lol :D

a ventilation system.

i donno, insense? none of my friends that ever had indoor plants ever cared about the smell

carbon filter

Yes, a carbon filter/scrubber. You can't just buy one and put it in your room and the smell will be gone, you have to get the whole ventilation system. Research the grow forums here, they can answer your question more clearly.