darkroom 120ii please help-set-up

im getting the sj120 for a first tyme grow experience. basically that's all i know other than i live next door to my landlord, and smell has to be completely gone. it's going in the attic so im fine there do i need a cool tube yes a carbon filter but all the spec's r driving me crazy i have searched read and read and it's all different. i would like to do the t-5s hps/mh probably 600 watt or do i need a 100? can i vent carbon filter into the attic or do i need to go outside? (share attic with landlord!)
how many plants can i grow in there? legally i can grow 12 thinking 6veg 6 flower. do veg plants smell? looking 4 any and all help possible. i noticed alot of it is old post so please any and all would be appreciated to a up and coming grower.

Alot of people say their veg plats don't smell but mine do. Stinks up my whole basement.