The Refining Forge is probably the easiest crafting station to use in Ark. To make Gasoline, simply put in Oil and Hides. Light up the forge and you'll get your Gasoline. For more information on Gasoline, check out this page: Gasoline In Ark
To fuel the Refining Forge you can use Wood, Thatch, or Sparkpowder. All of these will work well. Wood will produce Charcoall as it burns. With Thatch you'll go though a lot since it doesn't last long. Sparkpowder lasts the longest and isn't that hard to create.
Don't worry if you put in too much of a raw resource, it won't be wasted. The only thing that the Refining Forge can waste is fuel. It will keep running until you turn it off or it runs out of fuel. That means if you have extra Metal Ore, Hides, or Oil in it, they won"t get wasted. They will just sit there.
Bulk processing with the Refining Forge couldn't be easier. Simply build a few of them, then load them and light them. It's that simple. You don't have to sit there and watch them work. You can set them up and wander off.
On the Ark you have a few different crafting stations as well as crafting in your inventory. These you have to craft before you can use them of course, but they provide you with advanced crafting options and allow you to craft even more Engrams. And unlike Inventory crafting, you can use many of these crafting stations at a time.