Hello jk, and jr, welcome to the forum.
The 'roof' heat shield or radiator surface makes this stove look like one of the Surdiac models. You can do a search for 'surdiac' and you may find some info.
For general help, take a couple more photos of the doors, the air controls on the doors or the stove body, the firebox and ashpan. This way we can get an idea of the way it is designed and be able to help you with it.
In general, get a good hot wood fire going, slowly add coal to the wood fire, untill you have a full bed of burning coal. Then add as much coal as you can, the deeper the bed of coal the better.
Shut off all air that goes above the fire, this air is for burning wood, open the air vent that feeds air under the coal grate. Adjust your heat ouput with this under-grate air.
Hope this helps, Greg L