You only need to upgrade your armor twice to get this achievement. When you make your first camp fire, you will notice that you can craft armor with the second to last option. To craft your armor, you’ll need to gather leather, bones, and sticks. The only way to get these items is to pick them up off the floor as you’re walking and by pressing

. Basic armor, “Bone Bracers”, is made with 3 Bone, 3 Sticks, and 2 Leather. Max armor is made with 5 Bones, 5 Sticks, and 3 Leather. My best piece of advice is for you to have patience while you’re learning the game in the beginning. When you fight enemies, try to not take any damage. If you do manage to take damage, let them kill you and try again. You’ll spawn 10 seconds before the fight and you’ll be able to try again. If you don’t let the beginning enemies damage your armor, you should be able to max out, and get the achievement, by your third or fourth campfire.
In addition, if you just want to keep playing after taking damage, you can always repair your armor as long as it hasn’t been damaged too badly. The only downside is that requires the same items that you need to craft your max armor.