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Thanks HomeInMyShoes & i_am_hydrogen

I just want to put it into my words to see if I get it, feel free to point out where I went wrong.

Aperture.

Measured in f stops. Higher f stops mean smaller aperture (opening). Lower f stops mean larger aperture. Larger apertures are better for night photos so that more light can come in. Larger apertures help focus things in more. Going one down f stop will double, going up will halve.

Shutter Speed

It is measured in fraction of second(s). It determines how long the camera is exposed to the photo. Higher numbers (eg 1/1600) happen to freeze whatever motion is going on. Usually it depends on the zoom of your lens. If you're at 53mm, going 53 and higher can freeze the photo. Going under will blur motion. Usually going more than a few under will require some support as it will blur easily. If you go to low, the photo will be completely white, if you go too high the photo will be too black.

ISO

How the camera reacts to the light hitting the sensor. Higher ISOs are better for night time (because ... ?) but often times they will be more grainy.

Any close?