How do you heat the oven?

Take a rock from the pile of rocks by the steps , you villager will put it in the fire and heat it then they willo take it to your oven and place it.

You first drag a master farmer onto it and they will heat it but then it will say there is nothing to cook in the oven so go to the rock pile above, to the right of the table where you get tec points and there should be some rocks there. If you put someone on it, it will say they are preparing the oven but I am still tying to figure out what type of person can do it cause normally they are halfway through doing it and it shows an X sign and they walk away. Hope I helped!

I just dragged my master builder to the pile of rocks, at the base of the steps, by the fire, and he gathered a rock, took it to the fire, got it hot then took it to the oven. However, I have nothing to cook yet. But it did prepare the oven for cooking

Drag an adult villager on the rock pile to the right of the fire or. He/ she will prepare the oven. I used an adept builder.