Hi
I'm relatively new as well, but believe the light bulb has come on for me - stick with it because it all falls into place after a while. I found that reading what the more experienced members on forums like this one are doing (and then turning on the camera and trying to do one thing at a time, take lots of pictures) is the best way to learn.
Anyway I thought to myself, maybe I'm just about confident enough now to offer a bit of advice on exposure (gulp) so here goes.
By the way this is a newcomer talking to even more of a newcomer, so bear that in mind, all I'm going to try an explain is where I've been (which is where I think you are) and what I've learned - I'm sure if I get anything really wrong, someone will correct it.
Think "light control" to me that's what I believe the basics are about. how much light falls on the film. Now, obviously digital cameras don't have film anymore, they have a sensor - so replace "film-strip" with "sensor" in your head.
There are four things that control how much light falls on the sensor and those four things will affect the "image" that's recorded onto the camera.
One of them is external, how bright is the environment you are shooting in. This of course can be controlled by shooting during the day, at night or using flash and/or lights. The other three are options within your cameras controls
If you took your sensor out of the camera (and think of it like a sponge) and left it on the table then, assuming "normal" lighting the sensor would continue soaking up the light until the "image" it recorded was pure white. If the room was pitch black, there would be no light for it to soak up and therefore the image would be pure black.
So obviously you need to control how much light the sensor (sponge) is soaking up when you want to take the picture. And if you follow the logic of the previous statement, then the darker the environment is the longer you would need to expose the sensor and the brighter the environment the shorter you need to expose it to the environment.
I won’t touch on "altering" the external lighting by flash and other light sources for now, but concentrate on the three camera settings as I think that's what you will be struggling with.
So, assuming normal daylight conditions in your front room. The three things you can control in how much light the sensor soaks up are
1) The aperture - how big is the hole when the shutter opens. Bigger hole, more light
2) The shutter speed - how long is the hole left open for. 1/250 of a second won’t let in as much light as 2 seconds
3) ISO - how good is your sensor (sponge) at soaking up light. You can make your sponge better at absorbing by increasing the ISO setting. So ISO100 means you've got one of those smooth looking sponges and no matter how much light you throw at it, it doesn't really like absorbing it, but the light it does absorb results in a "clean" image on its smooth surface. A sensor (sponge) with an ISO of 1600 is a much more absorbent one (one of those sponges with bigger holes) and just love's light, it "sucks" it in through the smallest of openings, but the image rests on a rougher surface so is less sharp. Now obviously you don't replace one sensor for another one, but altering the ISO from a low number to a higher one, means that if the size of the hole (aperture) and the amount of time it's open (shutter speed) stays the same, the higher ISO setting will absorb more light. The downside is that because it's sucking the light in at a faster rate it gets a bit sloppy and doesn't have the time to record the image properly, it's a "bit rough round the edges" or "noisy" and the image gets "grainier" the higher the ISO used.
My suggestion would be not to get too hung up about the f stop numbers, shutter speeds and ISO numbers. Try and think of all three in terms of "stops". If you move any of them one stop up, the resulting image will be brighter and vice-versa.
My suggestion would be to put your camera onto manual straight away, go to a normally light room and start taking pictures playing around with the above three settings. If you switch your camera on and put it to manual, aim at an object and press the shutter what's the worse that's going to happen!
If the viewfinder shows that what you've taken is too dark you've got three options. Slow down your shutter speed, open up your aperture or crank up your ISO.
Now this is where you find out where the tricky bit takes over, because altering all three of these has different "side effects".
If you slow down the shutter speed, you'll find that beyond a certain point you can't hold the camera still enough without causing it to shake while the image is being recorded, so you'll end up with a blurred picture.
If you can't slow down the shutter speed anymore, you can open up your aperture. However the wider that becomes the shallower the depth of field becomes. This is where the vase of flowers you're shooting is in focus but less of the foreground and also the background beyond the vase is in focus. If you’re shooting a landscape, that might be a problem as you want as much of the view to be in focus as possible. However, if it's a portrait and you want to get rid of a distracting background by blurring it then opening up the aperture will do that.
If you can't slow the shutter speed down anymore and you want to keep everything in focus so you can’t open up the aperture anymore without blurring too much of the image, then you can start to increase the ISO until the image is correctly exposed. Bearing in mind the higher that goes the grainer the image. Again that can be a negative if you want it pin-sharp. But it could be a "look" you are going for if you want to evoke some sort of feeling - street photography at times looks good if it's grainy.
However, if you make yourself a mug of tea and put it into manual and shoot the same image over and over again until your finger goes sore, while all the time changing all of these three settings in all sorts of various combinations, you'll soon get a "feel" for what you need to change to get the exposure you want and also the "price you have to pay" sometimes to get an image.
Hopefully this has been of use, just thought I'd try and pay back some of the good advice I've absorbed on this forum and try and help someone out.
Once it clicks, you'll find that you start to feel like a photographer and a bit like driving, where you are spending less time working out what your hands and feet are doing and concentrating more on what is going on around you.
Once you've gone beyond my "Janet and John" explanantion then this is a very usefull little resource in explaining things properley to you
http://www.cambridgeincolour.com/tutorials.htm
Seriously, there is a wealth of information here and any questions you have just ask away. We're a firendly bunch and always happy to offer help and advice 
