Your camera most likely have some priority settings. Being able to set the program to A for the aperture (can be named otherwise on your camera), you will get to manage the aperture which lets you control the depth of field, and let the camera figure out the other settings, pr. auto. A small or tight aperture hole is a bigger number what will give you a deeper depth of field.
So the smaller number makes a larger hole- aperture, and will give you less depth of field.
Simply; if you want a shallow depth of field, then your F-stop number should be small.
If you want a deep depth of fields, your F-stop number should be higher.
Also, you have an S program (S for shutter, again it can be named otherwise), where you can set the shutter speed, useful when shooting for example sport, where the speed is your priority.
You can set the wanted shutter speed, and the camera will adjust the other settings automatically, so your pictures will turn out good.
Setting the camera to M (or other) for manual, you have control over all the settings. Depending on your camera, there are different wheels to turn, and buttons to push.
But in Manual mode you have control over all the settings.
For this see more about flash-meters here..
You can also set the camera to work fully automatic. This will manage all the settings. But if you have a shutter priority or you want your idea about how depth of field should be, then, use the appropriate mode; A. or S. (On the Nikon).
ISO is about the sensitivity of the film sensor. Generally, a lower number will need more light, the higher will mean that the film is more sensitive, but this will result in more grainy pictures. My general ISO setting for studio photography is 200. If you are in need of light to get your chosen shutter speed to work, you can set the ISO to a higher value.
But mostly I just keep the ISO at 200, but adjusting it according to the need.
I make much use of setting the ISO to a high number, if I need light. I maybe also not want a slower shuter, or a more low-depth result. So, f.ex. in a restaurant I dont mind turning up the ISO to 640, yes, or even 6000. My camera can manage it, and honestly, I use most pictures ont the web, so the noice that there might be, is not visible. You would have to tak two pictures with same view, to compare, and zoom in on. What I mean is that its like people fear the ISO and will do all to avoid turning it up. Rather go for a slow shutter (camera shake).
Another thing to take in mind is the white balance. If you shoot RAW files, then you can do the setting of this in your chosen software for managing RAW files. You can use a gray card, or a white, for when working in post processing, to set the correct white balance.
You use the white balance to get all the colours looking right. If you have, what should be a correct white colour in your image, you can let your software work from that as a base to set the other colours from.
When working in the studio, I always shoot in manual mode.
But I do have a priority being aperture, and the shutter speed mostly is not really of matter, since I most often will be shooting portraits or still life, and have lots of lights to work with. Your camera's, - or the sensors, resolution, is measured in MP, Mega Pixels. A feature that constantly is increasing in newer camera models. A size could be 4928 x 3264 pixels, being 16 Mega Pixels.
The camera will use a memory card, at where to store the pictures. They come at variable storage capacity, and prices. Not all cameras use the same cards. My Nikon uses SD for example. One of the Nikons takes two CD cards and they can be used in three ways. First you can startwriting to the second card, when the first is full. Or you can use it so it writes RAW files to the first card, and JPS's to the other. Ot the laste option, and that is the one i use, its where you write the pcitures to both card at the same time. This way you will have a backup if your one card fails.