If you buy the gun new, you will receive a manual with it. Much will be written by lawyers (the "DO NOT POINT GUN AT HEAD" kind of thing) but read it anyway. A conventional double action revolver is about as simple a gun as can be made. Modern style revolvers are loaded by pressing a latch (its location varies with the maker) and swinging the cylinder out to the left. The chambers (round holes) in the cylinder will be obvious. Put the cartridges in those chambers, bullet end first. Make sure the cartridges are all the way in. Close the cylinder by pressing it back in. Do not "flip" the gun or use excessive force.
The revolver is now ready to fire. You can fire it either by pulling the trigger, called "double action", or by pulling the hammer (the thing with an "ear" on the top rear of the gun) back until it stays back, then pulling the trigger, called "single action". The former is faster, the latter has a shorter and lighter trigger pull.
Once all the cartridges have been fired, swing the cylinder out again and use the ejector rod (the thin part that sticks out of the front of the cylinder) to eject the fired cases. Then reload as above.
That is it. Other revolvers, like old style single actions will be a bit more complex to load and fire.