If the door switches act like normal reed switchen then it is correct that you can put one wire to ground and the other one on an input of the arduino.
Internally you can set the pullup resistor on the pin and check when the signal goes to low, to detect that the door is closed. If the door opens and the reed switch is open, you will get a high signal from the input pin.
But you can also connect one pin of the sensor to 5V and the check if the output pin of the sensor goes to high when the door is closed.
For the movement sensors you have to check the signals. There should be at least 3 pins for each sensor, power, ground and the signal itself.