Take the loose pickets from the fence, then climb down the ladder. Look at the note on the red door, in particular the letters AGA. Click on the bottom solar panel on the roof and solve the puzzle (match up all the wires by turning the individual panels). Now open the red door with code 171 (corresponding to the letters AGA from the note).
Look at the pictures on the walls, then look at the keys hanging on the wall and choose the 3 matching the silhouettes. Open the right door to reach the next small room. Use your keys on the power panel to unlock it, then open it. Solve the puzzle (connect wires 1-4, 2-7, 3-5, 6-8, 9-11, 10-12).
Leave this room and climb the stairs. Look at the drafting board and solve the puzzle (A5, A8, G8, G10, J10, G7, G5, F5). Turn the crank on the gramophone to hear and see a melody. Go back downstairs and click on the door beneath the stairs, opening the lock by repeating the melody you just saw (start with the red note representing A, and play the melody AEFBE). Open the door and take the binoculars. Go back upstairs and go out the door at the top (down to the right).
Head over to the right and look at the underground connector (the red arrow pointing at the ground indicates where it is). Look at the village in the distance using your binoculars. Return to the house a through the top door. Look at the book on gramophones in the bookshelf, in particular 9#, one, 2, three, 2, one, 1887. Go downstairs and look at the cabinet under the sink. Enter 3 codes here: 123, 211 and 887 based on your findings from the gramophones book. Take the spanner and electrical wire. Back out and enter the room under the stairs again. Use the spanner on the bicycle twice, and take the dynamo hub and poles.
Return outside and up to the underground connector. Use the poles, dynamo hub, pickets and wire on the connector in that order. Go back inside and downstairs, and into the room on the right. Look at the electrical meter and press the red button.