Hi.

I have 300 iron ore how to add it to furnace. There is a key shortcut?
Or only possibility is clicking add item 300 times?

Hi,

When you interact with your furnace, a window opens with several tabs. The first one is for fuel.

If you feed you fire with a lot of wood, you'll be able to melt, cook... the amount you want by simply clicking the item (metal, recipe..) you need and using the right/left arrow icons that show up.

Yes you have to click the increase button over and over again. Which is bad and needs to be patched for both adding ore and adding fuel for dealing with large quantities. I had 800 firewood a zombie chopped up and learned this the hard way.