Simple electronic code su circuit

Working principle of the circuit : Press button S first to trigger the monostable circuit of the chip NE555 (IC.), and
its output becomes high, causing the relay RL to pull in. After the pull-in, the 12 V power supply passes through the remaining parts. This period of time is about is 10 s. At this moment the LED is glowing. Within this 10 s , you must press button S4 to trigger the conduction of VS, and then press button S5 to make the next VS2 close and the lock opens. At the same time, the buzzer PZ will sound, indicating that the lock has been opened.