The wood or plastic deck of the skateboard is simply what you stand on. Obvious, but there are lots of different kinds. Softer, bigger wheels will absorb bumps better and have good traction. Harder, smaller wheels are best for technical tricks, and they slide out more easily. The metal part that attaches the wheels to the deck.
Tight trucks steady the board, looser trucks make the turning more responsive.
You can tighten and loosen them on your own, depending on your style and where you are riding. It's a good idea to experiment with your trucks. Step 2 Figure out where you want to ride. That will help determine the type of board you need. It's long, and the wheels are big, fat and soft.