Just see the title

Just see the FAQ:

• https://www.curseforge.com/minecraft/mc-mods/brick-furnace
• https://modrinth.com/mod/brick-furnace

Where is the config file?
There is a defaultconfig directory, where you can find it. If you change something there it has only an effect on new savegames. For existing savegames you need to go to the serverconfig directory of the savegame.

The name should be clear: "brickfurnace-server.toml"