What camera settings do I use?

Ok, I took photography for 2 years at a-level, and eventually i bought a couple of lights with umbrellas and a white backing sheet and frame.
i know i need the ISO low to prevent grainy photos But, i'm struggling to find the right photo, i've spent all morning attempting trial and error changing many settings but - What main settings should i be concentrating on, i was not taught how to work in a studio at 6th form so any advice would be most appreciated.
i need to set the white balance when the studio is all set up with lights on, i also have continous lights but when i get more in to it i'm hoping to buy the flash ones.
I also have a nikon D60 and hoping to upgrade very soon. Any advice would be so helpful: D many thanks!
Louise.

Added (1). And To 'Jimmy' I did mention WE WERE NOT TAUGHT HOW TO USE A CAMERA IN A STUDIO! Nor were we taught to set up a studio…
so this is all new to me. Just be helpful rather than an ignorant ***. And yes thank you i passed both as and a2.

Added (2). And To 'Jimmy' I did mention WE WERE NOT TAUGHT HOW TO USE A CAMERA IN A STUDIO! Nor were we taught to set up a studio…
so this is all new to me. Just be helpful rather than an ignorant ***. And yes thank you i passed both as and a2.

We should be asking advice from you, not you from us. You've done the A levels. Thing is, did you pass? Sounds like not.

You are correct about a low ISO, BUT without seeing the actual studio setup (amount/power of lights, their location and distance from subject; wall colors; backgrounds; etcetera) and the problems you are having, it is hard to give specifics.

As far as settings, I use manual (camera and lens). Depending on the lighting and the subject, the aperture and shutter speed will vary. I normally set my ISO at 100-250; base the shutter speed on the subject (a product or a living creature) and whether or not a tripod/shutter release is used; and set the aperture to give me a decent DOF (use a DOF calculator until you get familiar with each lens… Http://www.dofmaster.com/dofjs.html ).

You don't really say anything else about what you are trying to achieve, so it's tough to offer advice.
If you are just trying to eliminate grain, is that really an end to itself?
Set your iso as low as possible.
Manually focus.
Now depending on lighting you'll have to set your exposure and your aperture. These are dependant on each other, and focal length. As a rule the fastest aperture for your given focal length, stopping down, your lens will sharpen up. For instance my f2.8 is sharpest from f4-f8 (give or take) bear this in mind and set your aperture, then set your exposure to fit.
Shoot on a tripod. In a studio there's no excuse for not doing this. It will give you shaper images. Use a remote release or the self timer.
If you still have grain issues (noise) look to get a program called Noise Ninja. I's the only program I consider as essential, and I don't even care about noise. It works as a plugin, externally to lightrooom, or standalone.
Your other alternative is to forget about noise. Look at great photographers, how many of them care about grain, or even embraced it as an element to exploit.

Do they not teach 'sunny 16' as part of the curriculum for photography? If you learn this, as a start, you'll never go to far wrong.

ISO100
Shutter and aperture - camera on manual, metering mode to spot and take a spot reading from your subject. Start with that and examine the histogram. Adjust the exposure by half/third stops until you are happy with the result.
White balance - auto

Shoot in RAW format so you can post process to fine tune

Without knowing what you're trying to achieve it's pretty hard to advise on what you should be doing. Your destination will determine how you light a subject so you need to figure that bit out, and then tell us.

One thing I can tell you is that you don't need to worry about white balance, just shoot in RAW and then deal with it then. What is important is making sure that your bulbs put out light in the same colour temperature, otherwise you're going get colour casts.