What now?

I have found the Mirthril forge. Went down inside the deep crevasse to find Mirthril ore so i could craft that Mirthril spear at the forge, which unlocked the prompt to find the dragon/bone horde location. However, I dont have any other Mirthril items to build (finding the forge and the ore didnt unlock the crafting plans for armor, etc.) so do i just go find and fight the dragon now? Feels like I'm missing something.