A little advice, you will want to get your grow area set up before you even start germinating the first seed, as it can take a lot of tuning to get the evironment correct and stable. For a 400w light, I'd recommend no bigger than a 4'x4' floor space. For the fuorescent I'd say no bigger than 2'x2'. Personally I'd set up 2 different areas: one at 3'x3'x6' tall for flowering with the hps and one that is 2'x1.5'x3' tall for vegging under the fluorescent. Make sure the lights are sturdily hung on something that allows you to adjust the height as the plants grow. You will need to check the temps with them all set up and running, and adjust ventilation fans until the ambient temps are within range (70-85F). Temperature will be a little higher when empty than when you have plants in there btw.

There are several growing styles that you can use depending on what your needs and resources are. All of these can be found here and the many other sites & books dedicated to growing mmj. SOG, or sea of green, is a method where you can harvest plants every 1-4 weeks, thereby giving you a constant, staggered supply of fresh product. You can also grow them all at once normally under the fluoro, then put them under the hps and flower that way. This style is the easiest but it also takes a while so there will be at least 2 months in between harvests. There's also various techniques throughout the forums for pruning and shaping plants to increase your yield by letting the light hit as many bud sites as possible but start simple and when you get more confident then you can try these advanced techniques.

Search the forums for grow logs where they are using the same wattage lights as you to get an idea of what you can do with them, the set ups seem to be mostly based around the lights. Good luck, & happy growing!

p.s.- knowledge is power so read as much as you can!