This guy's post is spot onn but i'd like to add some things.
Adding co2 to the grow room helps but only under precise & heavily controled conditions,the ppm (parts per million) need to be within an exact range or its worthless,also light needs to be maximized in order for the plant to use the increased co2,i cant see any amount of cfl's doing the job plus many controls need be in place in the room even if lighting is enough.
These shake n bake co2 devices are not worth the time it takes putting them together.
If your a new grower like you say the best advice i can give you is to stop reading stuff right now,im not shitting you either,most new growers are their plants worst enemy,they read & learn way too many trick & gimmicks to make the plants better,then they apply everything they've learned all at once & fuk the whole grow right up,they read all kinds of crazy stuff like fox farms gogo juice & think they need products like "bud hardener" & end up with a confusing mess.
When your new its best to keep it as simple as possible & that is no lie,proper lighting,proper watering,proper fertilization & this means being very weak handed & using fertilizers very sparingly,do these 3 simple things & you'll harvest sticky fat ass buds in a few months,the more tricks you add to the grow the less your chances of success will be.