The two lids with removable centers for smaller pans are usually over the firebox. One to boil water with center removed, and one for cooking with center removed. The correct pan will have a smoke ring to seal to stove, but not necessary. You have to stay with the food, moving it almost all the time. It cooks fast and will burn quick. Almost like a stir fry.
The top is normally seasoned like a cast iron pan with cooking oil. It should be wire wheeled and sanded smooth down to clean metal, and a few fires with oil each time applied until a black coating forms from the oil. Oil again when not in use for long storage periods.
Reconditioning top;
Seasoning top after first fire. Yes, it's smokey when seasoning.
If it flakes or wears off in spots, reoil. Once seasoned, you will smell it if it gets too hot.
If the base isn't baked enamel, stove black is used when cold. Usually once weekly when allowed to cool to clean circulation area around oven. (you need to wire wheel the firebox area before stove blacking)
It should have a working damper in the pipe.
Ace Hardware has oval adapters.
The oven isn't going to work right with an air leak into chimney. That is the only thing keeping it from overheating with 1/2 damper. Cool air rushing in kills draft, slowing air coming into fire. Overnight, or when done cooking in warmer weather, you can tilt one of the lids near the exhaust to allow air up the stack to slow the fire.
You're not going to get the proper circulation around oven with the air leak at pipe connection. The proper draft is required to pull the heat around the oven. My oven runs about 300 with a normal fire. Pulling the circulator lever brings it up, and is easy to control. Small wood when using oven for higher heat. You will find they bake better than a gas or electric oven since there is little to no air flow. There is no vent like in a modern oven, so keep your face back when opening door. Steam will rush out depending on what you're cooking. Things also won't burn since the humidity is higher in the oven. It will cook faster, and not brown things like you're used to.
