I'm going to be honest here, it's easier to Google than post on Gaia. I don't see why people don't do it.
Crafting with Stalhrim has two major requirements, in addition to the required amount of rare Stalhrim ore. You won’t be able to mine without a special item, and you won’t be able to forge without first completing a quest.
Once you unlock the ability to forge Stalhrim, you’ll also need the Ebony Smithing perk to have the skill to work with this ore.
Step 1: Getting the Nordic Pickaxe
Complete the quest for the Blacksmith in Raven Rock to obtain the Nordic Pickaxe.
Deliver the Pickaxe to the Blacksmith, but he will let you keep it. You can now mine for Stalhrim ore.
Step 2: Unlocking the ability to forge Stalhrim
Stalhrim ore is useless until you can begin forging it.
Travel to Skaal Village. An NPC will ask for your help in rescuing the local Blacksmith. Complete this quest, and you’ll be able to forge this material.
Step 3: Gaining Stalhrim and Crafting
Stalhrim can be found in large blocks of what appears to be thick blue ice. It can only be mined with the Nordic Axe.
Stalhrim deposits can be found in Raven Rock Mine, the northface of the small island at the northeastern shore of Sothstheim, and northeast of Northshore Landing. There are many more Stalhrim locations, so keep looking and leave a comment below if you’ve found more.
Stalhrim is also prevalent in the dungeons and caves of Solstheim. Whenever you go exploring, check every corner to spot the deposits.
Next, simply craft the items the same way you would craft other weapons and armor. Find a Forge at a Blacksmith and use it. If your Blacksmith skill is high, you should find a new menu for Stahlrim weapons.
Craft any weapon or piece of armor to unlock this achievement.