aaaxl wrote:I guess it also gives me a couple of ready LEDs and a button that I can use, if I solder in some wires, right? How about the capacitors, they are not for my use, right?
Yes, the buttons and LEDs are just there for hooking up easily. The LEDs already have a connection to ground and a current limiting resistor, so you don't need to add those, just connect to a digital output pin. The S1 button is for your own use, but the other button is tied to the reset line on the Arduino, as it's difficult to hit the button on the original board under the shield.
As for the caps; they're designed to filter the ground and 5V lines if you install those. This reduces the amount of noise that might otherwise be injected from other parts of the circuit and affect your circuit's operation.