Admittedly, the tutorial was very rushed and completed in only one hour on the day of submission. Didn’t had time to flush out many things. But the order is:
Get mug -> collect water -> place it down somewhere Collect beans -> grind beans -> put grounded beans into mug with water Put mug + water + grounded beans on top of the fire place until its steaming, then serve it.
So yes you can actually put the tray + beans and mug + water down on the table with the G button :).
As for the customers, ermmmm, my excuse is, they don’t know what’s a coffee so they willingly took the plain water you served them :)