You need to get out of the cellar.
Take the PAN from the shelves in the back and put it on the stove. On the left side of the shelf is a crate where you can find a CANDLE. Use the candle with the pan. Left of the shelves is SOLVENT. Take it and add it to the pan. On the floor you can find FERTILIZER. Pick it up and add it to the pan. Take the pan from the stove and use the pan in your inventory to get the PLASTIC EXPLOSIVE out. Use the explosive on the door on the left. Now to detonate it.
Just above where the pan was there’s a box with cheerful stuff. Rummage through it until you find a FIRE CRACKER. Just above that box is a CAR BATTERY that you can use as well.
Take the RADIO from the shelf and use the toolkit on the radio to dismantle it and take the WIRE, the SPEAKERS and the BATTERIES from it.
Use one of the drawers from the desk to find the MATCHES. On top of the desk you can find a roll of TAPE. In your inventory use the matches with the wire and add the tape to it to stick them together. Add the fire cracker to the wire to create a detonator. Use the detonator in the plastic on the door.
Look at the mattress so you can use it as cover, then add the car battery to the detonator to set it off.
Game source: A copy of the game was found here on the internet.