First, you wanna know what a skateboard is. That is basic knowledge. You can get a skateboard-setup in many shapes, colors, thicknesses and weights. You just need to find your personal board, but that comes with the time.
The deck, is the long piece of wood you stand on when you're rolling down the streets. They have many shapes. When you're looking for a board, they can be 7.5" or up to 8.3" wide. Of course, the wider, the heavier - in the shop, try and stand on the deck, even if they do not have wheels on them yet, just to get a feeling between your foot-length and the board.
The griptape, is the black (you can get the griptape in many colors, but black is standard) sandpaper that you glue on the top of the deck, to be more solid standing on the board. It is also very important when you are making tricks like kickflip and heelflip. You can get the griptape in many different varies, some of them have very small holes in it to prevent bubbles under the griptape. Griptape is a little tricky to attach, but I'm sure the guy in the shop will do it for you, when you buy a new deck. In most shops, you get the griptape for free, when you buy a new deck.
The bolts, is the screws that you use to hold the deck and the trucks together. Can also be in many different colors.
The trucks, is the piece of metal, that is attached under the deck and holds the wheels. You can get them in many different models, colors, shapes and weights. Some like them very wide, some like them thin. There is two pieces of metal in the truck. The two pieces is held together by a long, thick screw called a kingpin. The kingpin is primary used to adjust the "hardness" of the truck - how much weight you have to use when tilting the board to turn. You also use the truck to grind on :)
The wheels, is attached on the trucks and have small bearings in them. You can get them in many different colors, weights and shapes. Some wheels are wider than others.
The bearings, is some small rings that makes the wheels spin. The bearings is attached between the wheel and the truck. The "spin-time" can vary very much from model to model.