Connecting mirror heating pads to switch in bathroom
Run the two browns (L) to your switch: supply on one side of switch, heater on other side of switch.  Join the two blues (N). Join the two greens (PE).  Make sure your method of joining the wires conforms to your country's wiring standard.

By the way, Brown is Line per IEC; Blue is Neutral.  Line is black in US and other countries not aligning with IEC.