Thanks for playing! I'm sorry for not making the game more readable, as I said to others I put off the tutorial too much and sadly I ran out of time. If you want to give it a second try, you refuel the furnace by holding the lid, not pressing it. The boxes contain a bunch of the products and you must first unload them on the shelf thats to the right of the counter, customers only accept products, not boxes.
Thanks again for the kind words and feedback :))