To obtain this cheevo, you need to craft 3 legendary items. As the name implies you need to craft top tier stuff, which is highly valuable.
Short Explanation :
1) Put 20 points in Intelligence or 18 in Technical Ability
2)Unlock Edgerunner Artisan (tech) or Bartmos' Legacy (int) perk
3) Craft 3 legendary items
4) Achievement unlocked, happy gamer.
If you want to obtain as soon as possible you need to create a character and put ALL the starting stats in one of these two options: technical ability OR intelligence.
After that you need to reach lv 10 while putting all the stats points in the aforementioned stats of your choice, by doing that you should have either technical ability at 18 or intelligence at 20.
THIS IS THE MINIMUM REQUIREMENT for crafting legendary items, because you need a perk that allows you to craft legendary items and this one will be able to be unlocked only if you have 18 points in tech or 20 in Int. (The perks are: Edgerunner artisan for technical ability and Bartmos' Legacy for Intelligence).
Once you obtain one of these two, you are allowed to craft legendary items.
You need a LOT of materials and a blueprint for crafting a legendary one. Don't worry about the blueprints, since you get a few from the main quest(if you go for the technical path, for the intelligence one you need to have the perk in order to get them). Materials can be a pain to find, so you may want to visit junk shop/netrunner shops to buy some extra ones.
IMPORTANT Since the perk tree is not actually a tree, you can unlock immediately the perk to craft as soon as you hit 18/20 on the stat. You don't need to have the uncommon/rare/epic one. HOWEVER, especially for the intelligence path, to craft the legendary quickhacks you need the epic version of that one. The epic can still be found on the world, from loot and quests rewards or you can buy them. So I'd recommend to have them to make your life easier. There are other perks that helps you finding more crafting components, but it's up to you if you want them or not.
Once you craft three items the achievement will unlock!