Yep, so once you press f12 and it brings up that window, there should be some tabs on the top bar of that window - "Elements", "Sources", something like that. One of them should say Console. Can you try to replicate the error, then open up the console window and paste what's in it?
hiya! not op, but here's mine: https://pastebin.com/axhTB83q - there's no error message/popup, it's just that there is no indication of how to progress with the game after presenting the item (e.g. sand) to the customer! thanks for troubleshooting