do you have 3 rooms that are 250 sq ft each, or are all 3 750 sq ft each, because that makes a huge difference...
if i was you i'd look into quantum boards to run my veg area, they use a lot less power, produce a lot less heat, and give great results.
you also have to keep in mind what kind of electrical service you have available. you're talking about 6000+ watts for this set up. thats a good bit of juice.
a 250 sq foot room, if its roughly square, will be 16 X 16. if you have the power available, 4 1k lights would do nicely, but if power is an issue, 4 600s would do almost as well, and save you a lot of wattage, as well as heat.
speaking of heat, you need to include at least one big carbon filter, an 8 inch extraction fan, the ducting to hook it all together, and a place to vent it outside.
you're going to need a ppm/ec meter, a ph meter, ph up and down, pots in different sizes to start and transfer plants into as they grow....what kind of medium are you going to use? soil, coco coir, promix, hydroponics.....all have advantages and disadvantages.....
fans for all your rooms to keep air circulating, hangers for your lights...and the ducting.
i started using expensive premixed nutes, and they did a fine job. i've since went to jack's dry ferts, and i like them a lot. i use the 20-20-20 for veg, and the citrus for flowering. i spray the plants once a week with blossom booster, a calcium foliar spray for tomato bud rot. the jack's doesn't have any calcium because it interferes with sulfur. if you foliar spray it once a week, the plants get plenty and it doesn't screw up the balance in your medium.
you need to think about pest control....during veg i will alternate spinosad and pyrethin, but once a plants started to flower, i only use spinosad, it has a short half life and low toxicity to humans to begin with. i hate neem oil, im allergic to it, it give me a rash, and it stinks like rotten chinese food, but its a decent product as far as results go.
....this is just a small part of it all....and its why people are telling you to start small and learn before you jump in with both feet...
if you still jump, expect to get splashed with shit before you get a good footing...
good luck