I would do a lot more reading and research (I must have done 2 months on and off before I did begin to invest and set it up .. and I did grow outdoors years ago)
ther are a lot of ways to do it ..
dont just think Bc. one say its great it is .. might be for him but not for you .. it all depense ..
your space and your money will for a start set a limit ..
stuff like tempetures will also play a role ..
but most importent is to ask yourself fist .. is what do I want .. what do I expect .. what am I ready to use in terms of money/time ..
big HDI lights like HPS and MH lights who was ment to be outdoor lights do produce a lot of heat .. so with them you will also have to invest around the same in ventilation .. tubeing .. filters .. and maybe a AC (not in the UK tho)
fluorescens tubes and CLFs can be great .. but they have one big down side .. penetration/strengs .. need to be on top of the plants to even get close to a HPS grow .. but make next to no heat and can be a cheap way to get enough smoke for yourself .. and a nice begining as upscaling is always a option .. shopping is easy
LED can be great (no experiance tho) but make sure you dont go cheap and buy them China toy lights ...
do the research .. see what other Ppl. have good experiance with .. go with a big brand .. pay them extra 50£ .. sucks to pay 200£ for a toy that dont realy work ..
about light and dark hrs .. pretty simple .. its like nature .. you know
just use commen sens and logic .. plant logic taht is
well fall arrives and days become shorter then the nights the plant will begin to flower (I think I read that less the 13 hrs of light will tricker that in most cases)
but ther is also the option of Auto seeds/plants .. might be a easy way for a beginner to get a foothold ?
as they dont follow the lenght of the days .. can just run it 18/6 or 20/4 as most do I belive all the way .. and no need to worry about light leaks .. witch can be a killer with normal seeds in flowering ..
nomather what you will need to "copy" nature so to speak .. it will need sun = light .. it will need rain = water and some wind and fresh air/co2 = ventilation and fans ..
you realy cant do this half .. you can do it on a big scale or a small or some wher in between .. but not half ..
need light .. need ventilation .. need odour controle/filter .. need fans .. and a good home for your girls witch also can be many things .. soil is most commen for beginners (I would suggest coco tho) also hydro is a way to make great yild .. but then you will also need a hydro system/pumps and what folow with that .. noise and space and more money ..
I could go on as you might notice
I reccon you need to get the basic in order to be able to choose the right way for you and your wallet and your needs ..
here is a great place to start .. can answer many basic questions and is easy to look things up:
http://www.420magazine.com/forums/how-grow-marijuana/81264-how-grow-marijuana-everything-you-need-know.html