1. Go to the Command Room. On the console to the right are levers to open the windows and shutters. Throw them. It's to the left of the Power Overview screen.
   
2. Turn around. Go out through the middle door.
   
3. Down the corridor to the right is a room with computers. Go into that room, turn right, and then turn left at the poster for the Periodic Table of Elements. Go right.
   
4. Follow the red corridor. Go through the door, and into the next room.
   
5. There are monitors labelled 1 to 4. Each one has a red lever under it. Throw the levers, and the consoles should light up.
   
6. Turn around and go back to the computer room. Follow them until you get to the December calendar. Turn right.
   
7. Go through the double-doors, and then through the next set of doors ahead. You'l be outside. Stop at the bridge. Turn right.
   
8. Elevator. Floor 2.
   
9. Turn left, then left. Go through the big blast-door.
   
10. On the other side, shlepp the three activated cores next to the door to the elevator on the other side of the bridge with the Gravity Gun. Go up.
    
11. Carry the cores through the left door, down the corridor, and then into the left elevator. Send the elevator up (do not get in it).
    
12. Get into the elevator opposite. Go up the steps.
    
13. Take each core out of the elevator on the other side of the wall ahead, and carry them through the door.
    
14. Around the perimeter in thirds is a hole for each core. They'll eat the core. Repeat for each hole. Three holes, three cores.
    
15. Go back to the Command Room.
    
16. Create a save game so you don't have to do this again.
    
17. Throw the Shutter and window levers again.
    
18. Throw the three Startup Panel levers. Doesn't matter what order.
    
19. Wait for the PA system to ask for confirmation.
    
20. Throw the Fusion Ignition ACTIVATE lever. Wait. It'll take a while for the signal to go through.
    
21. If you want the sequence to go start to finish, do not touch the MANUAL lever next to it. Else, if you want to prepare and stockpile while the core is warm, throw it.
    
22. Watch out the window, and occasionally glance at the monitors above the window.
    
23. If you hit the MANUAL lever earlier, this is your chance to scrounge new empty cores. The train depot will prepare to Deliver them every 20 minutes, and you can press the green button to receive them. When you're ready, throw the Fusion Ignition ACTIVATE lever again.
    
24. If you didn't hit the MANUAL lever earlier, the sequence will continue on its own.
    
25. When the sequence is over, you'll be in charge of making sure the bar under the reactor graphic on the overhead monitor doesn't go too high or too low. Balance the Influx and Stabilizer levers to do that.

Originally posted by Pixl:

My question is, is how tf you figured it out lmao.