The screen says " BOOT UP" therefore input the 6 digit code based on the booklet. In this case, it would be the code next to BOOT UP. theyre not all the same each game. so you have to check it manually.

"I don't understand what to do at the last stage. Can u help?"

At the last stage there will be a book with codes and a console that will ask you for specific codes to enter, like "boot up" or "open valves" There are then 4 terminals with 3 gauges that need to be brought into the green, then the console will ask for another code, repeat the terminals and console until you get the evacuation notification, there will be a chopper symbol around 100+ meters away that you need to get to the roof of to get out, The count down is how long the chopper will take to get there, not how much time you have left to get out, once it arrives you will have an extra minute and a half give or take to get on the chopper and get out, hope this solves your problem.

Updated.

This guide will be updated to make that more clear.

@alvanes The terminal will say what it wants you to enter, the codes are in a book on the other side of the room

I don't understand what to do at the last stage. Can u help?