once you have 3 runes or 3 meteorite ores in your inventory when you talk to the blacksmith in the talkbox you will see a hammer and anvil just click on that and when the window opens select the one you wantA few things to note are only silver swords can be branded with runes and only steel swords can be branded with oresyou also get a bonus when all three ores or runes are the same and one more thing the blacksmith will not do it for freeThere is a difference between a rune and a runestone. Runes to be branded into silver swords are square shaped whereas runestones you can apply yourself ,you use them just as you would a whetstone
One thing to note is that the game is a bit misleading when it comes to the steel sword. It's called REforging your sword, but what actually happens is that the blacksmith makes you a new steel sword from the meteorite ore. Your old steel sword isn't reforged; it will still be in your inventory, unchanged.When you get a new steel sword forged from meteorite ore, the blacksmith's shop window will open, and in his inventory will be a brand-new sword, made with your ore. You have to buy it from him as a new item.