Set your brightness level to max:

Grab the following:
Gas Mask:
Flash Light:
Backpack:
Can:
Bottle 1:
Bottle 2:

Then exit through the door:

There are three valves you have to turn to make three steam areas disappear. These are pretty sensitive and may take a few tries.

First:

Second (below the first):

Third (other side of the wall):

Go through the other side and grab the wheel:

Go back to open the door. You will have to hold the mouse button for a bit to be sure it fully opens.

Follow the trail until you see a pond and a house. Pick up and do the following:

Lighter on the bench:

Kindle in the shed, next to the house:

Light the lantern on the desk:

Open the stove door and light the fire:

Continue the trail after time has passed. Go in the next building, look for the safe here:

The hint is on a poster in the wall. Otherwise:

Grab the item:

Head back out, then make a u-turn down the hill.

The solution to the puzzle is a bit vague with the note on the top. Here are the steps to complete it. If the screen automatically exits, you've done it right and you can go through the door.

Head up the hill and grab the music sheet on the floor:

Head to the back, and interact with the piano:

You finished the game. Enjoy :)