The minimum wiring for a switch is to connect the switch between the microcontroller pin and ground, then in the sketch, turn on the internal pullup resistor. This will cause the pin to be HIGH when the switch is open (or if it's a normally open button switch, when the button is not pushed), and LOW when the switch is closed (button pushed). That might be backwards from the obvious way to think about it, but it saves the external resistor. For two or more, just connect each switch between a pin and ground.
Set the pin up as follows:
void setup(void)
{
pinMode(2, INPUT_PULLUP); //set pin 2 as input with internal pullup resistor enabled
}