Finding a troll will be the first step in crafting troll hide armour.
Guide to Find a Big Blue Troll
Step One to find a Troll! Load up Valheim and create a new world.
Step Two to finding a Troll! Venture around your world until you come across a Black Forest. The Black Forest will have very tall spruce trees.
Step Three to finding a Troll! Once you have found a Black Forest you will have to go into it. There are two areas where you can a troll. A troll can be spotted walking around the Black Forest or can be inside a troll cave which are scattered around the forest. The caves can be spotted with bones outside the front.
Step Four to Finding a Troll! So you have found a troll! The best way to kill the troll early on would be to fire arrows at it. Running away, turning around, and firing at the troll can be an easy strategy. Repeating that strategy should result in the trolls death.
Congratulations! You have killed the troll and obtained the troll hide! You will most likely need more hide to make the troll hide armour. Repeat this guide again to obtain more troll hide. Once you have gathered enough troll hide you can craft the armour at workbench.