Let me try to be simple and short.
F-stop is the hole size through the lens and it is adjustable.
Shutter speed is how fast the shutter opens and closes and it is adjustable
Lets put it all together The shutter opens and closes and allows the light to pass through the hole in the lens.
As you no doubt have noticed the shutter speed and the F-stop or (aperture or hole size) is adjustable. Light changes so you need a camera that can change to adjust to the changing light. Hence the adjustable feature of your camera. The adjustments also have a name called "stops"
You need to adjust the camera so that it gets a proper amount of exposure to the amount of light that exists.. If you want to learn what the proper exposure is for a new lighting situation then put the camera in automatic and note what settings the camera selects. You can take photos and never leave the auto setting quite fine. If you have no auto setting you no doubt have a meter needle or similar. Just see if it says it is a good combination of shutter speed and f-stop.
If you can use auto setting quite nicely then why all the settings. A few reasons
1) The auto light meter wants to make everything gray. Thus to make white snow white and not gray you override the auto setting and allow more light in to get the white snow back to white. The same for dark objects except you let less light in to keep the object dark
2) You may want to favor the extreme end of shutter speed to avoid blur
3) You may want to favor the extreme end of F-stop to take advantage of the depth of field phenomenon Or in other words control how much is in focus.
4) The meter has limits. You can't meter for a midnight dark of the moon shot of tree leaves. Thus the camera has a long long shutter speed setting called bulb where you open and close it per your wild guess.
5) You need to set shutter speed to properly work with a flash unit.
That is about it. All those pretty picture dial settings do is to arrange to set the camera per the above description of the basic functions I described.
Read the manual here
http://ca.konicaminolta.com/support...ynax_maxxum_400si/Maxxum400siManual-Part1.pdf