sounds like you need to do some reading man..theres plenty of grow books.videos..google.utube can help you out quite a bit.and theres tons of info how to grow in here..do some research man..just type what your looking for in the search forms..tons of info...
newbies have tons of questions..understandable..but you should at least try to help yourself first. not just put a seed in the ground and ask a million questions..thats like getting behind a wheel of a car and not knowing which pedal is the gas...
and im not trying to be a smartass.it comes natural from what the girl tells me lol, no 2 grow rooms are the same..forget what you learned and learn your plants...and remember freash air is your friend..
and to answer your question..stick it near the plants...hot air rises..u wanna know what the temp and humidity is where your plants are.
temp should be between 65-75.if it gets hotter.make sure they have plenty of water...
u shouldnt have to worry much with cfls..keep them as close as possible. shouldnt be anymore than a 15% decrease in temp when lights are off.
the humidity should be around 60%,80% is even ok.plants thrive on high humidity.
when budding keep the humidity around 50% or lower.lower is better then.
they are young yet..the lighting hours are ok..18/6.20/4 whatever your heart desires.
u can start adding some nutes if ya wanna..only do 1/4-per gallon tho right now..dont over do it.if you mix it a lil weak,you wont have to worry bout killing your plants at this stage.
as they get bigger.up the dosage to 1/2 and so on...
that dont seem like much light for how big your closet is..that closet is a double door right??,if so.it looks like what im thinking it does..make sure you have some kinda reflector on the top of that light.to shed the light to your plants..otherwise most your light is escaping,cfls lumenins come from the side of the bulb.not the bottom like regular light bulbs..
id at least put a black tarp half way in the closet..get a couple more lightsin there when they start to get bigger..veg room.and a flowering room. would already be setup.
paitents are the key....
keep us posted.everyone loves new grows.