To make crystal walls in Valheim, you will need to find crystals and make a wooden hammer.
If you don’t have crystals already, you can get them from Stone Golems that spawn in the highest points and often around abandoned huts and keeps in the mountain biome.
However, before you try and find these stone golems, we highly recommend making the following preparations.
Once you have everything listed above, you will be good to go to face Stone Golems and farm crystals. Just use your iron mace and shield to parry and use quick combat combos on Stone Golems.
You will also want to focus on staggering golems so that you can quickly kill them while they are stunned. Keep it up, and you won’t have any problems killing golems, and after they die, you will get the crystals you need for crystal walls.
When you have at least two crystals, you can place crystal walls by finding them under the wooden hammer building section - under the building section, locate crystal walls at the bottom of the tab and left click to place them.