you can really make it as simple or as complex are you willing to to commit to based on what I'm guessing a) money b) time c) location d) other things. I started a room last year with the intent on making it a full blown high end sog hydro ponic system. Unfortunatly I was out of work and was unable to complete my dream room, but I still was able to grow my own bud in soil and smoke it. My 4 plants I grew for the first time provided me enough smoke for me and my mate for 4 months. Im finally working and recovering again and have been stable for 10 months now. I'm hoping to start working on my room again soon.
My advice, find out what you want and/or need, and then figure out how much you have to spend, and how you plan on growing it based on what I said before: a, b, c, d etc...
I'm sure others will chime in with more specific steps.
But most of the time will be spent on lots of researching on here and other sites. Once you decide on what you want, then it will be easier to decide on the method on which will get you there. Browse around to find the type of op that best matches your needs, and then scale and customize the op to your specifications.
Good luck