Outlast

OK so in order to get this Achievement you will need to restore power back to the Administrative Block.

You will need to venture down into the basement via the stairs near the elevator after leaving the Security Room.
Once in the Basement you will need to Activate the 2 pumps which are in 2 of the rooms around the main control you then need to locate the electrics room which is through the door which is originally locked when you enter the Basement you then throw the breaker and finally turn the power back on with the main control at the beginning. There is a guard patrolling the Basement so you'll need to watch your step.

The Achievement will pop after you finish the final step.

Below is a video I made for the Achievement. This was my second playthrough im making a full guide so the Achievement will not show but if you follow it you will get the Achievement.

This achievement is fully story related, when you get into the house you will do a sort of tutorial on the buttons and a few jump scares but this achievement starts when you get to the surety office and the lights go out. You need to go to the basement and follow the corridors till you get to the main power board which you will have to activate two generators and a switch to use.

Generator one and two are in the rooms directly in frount of the power board. So are easy to get except there is a catch, and that is that there is a guard walking round so you need to hide after activating the switch and not let him see you.

The power switch is located in the corridor to the left of the power board. That corridor is locked at first but will unlock after you activate your first genirator. If you go left then right then take the door on your left you will find the power switch there. Hide after activating it till the guard goes then make a run for the first room and the power board will now let you activate the power again and the achievement is yours.

If you would like a video guide for this I will leave my video guide below