The design of indoor distribution box connection diagram should be clear. Do not confuse the zero line with the live line. If the two lines are wrong, there will be no power supply. As for how to distinguish the two, do not make a mistake. You can look at the leakage switch, which is generally marked. If the letter is n, it means the zero line.

If you buy the indoor switch, you need to connect it to the main switch in the room.