well, i guess you were using one of the automatic modes mostly then...

ok basics,

shutter speed = time shutter is open exposing light to film, or in a digital camera, the sensor. this controlls how much light exposes the film, if something is moving, and the shutter speed is slow (like 1/20 a sec, 1" or such...) you will see a blur on the resulting image. when its a bright light, you will se a light trail, like this shot from my gallery:
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apeture: like shutter speed controlls the amount of light that gets in, but differently. the apeture relates to the size of the diaphragm in the lense, the bigger the opening, the more light gets in, the more your film is exposed. the notation is like f/x where x is a number. when the number is larger, that means the opening is smaller, letting less light expose the film. one advantage of this is that you usually get a sharper image this way. the problem is that when you have a smaller apeture (larger x) you need to have a longer shutter, so if you shake the camera youll get unwanted blur. now when you use a larger apeture, youll expose the film more, need to use a faster shutter. there is also two other results; more noise and a smaller depth of field. depth of field refers to the area that is in focus. with a small fepth of field, you can focus on an object, and whatever is behind the object, blurs out. the smaller the depth of field, the more its blurred out. this is how a lot of portrait shots are taken. look at this photo from my gallery, the only thing thats in focus is the part that says churchill en tubo
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ISO refers to a standardization for film speeds. basically all you need to know is the higher the number, the easier the film is exposed, meaning less light it takes to expose it right, resulting in a need for a faster shutter speed and a smaller apeture (f/a bigger number). with a higher iso, you will get more noise, and your image is usually less sharper, sometimes there isnt a visible difference, but other times there is.

i suggest looking in your manual on how to use Av, Tv, and the M mode on your camera. Av is a shutter priority mode, you can change the apeture to what you want, and it will automatically give you the shutter speed for best exposure. the Tv mode is the same, but for shutter speed, automatically giveing you the apeture for best exposure. in M, manual mode, you can adjust both, i believe you use the left and right arrows to increase and decrease, and press set to switch between changing shutter and apeture.

iso can be changed in all these modes, i believe by pressing func and then going to iso and selecting the iso you choose.

experimentation is the best way to learn all of this.