Step 3: How Does the Circuit Work :
When the door of the wardrobe is closed, the door presses against the SPDT Switch. The SPDT Switch causes the circuit to be open, hence no current flows and the LED Light is tuned off.
When the wardrobe door is opened, the SPDT Switch is released, as a result the circuit is closed. Since now the circuit is closed, current flows to the LED Light and it is turned on.
The given diagrams will help in visualizing the explaination.