There are four Witcher gear sets, you need to complete one to get this Achievement. The Treasure hunt Quest can be started from picking up Notes, they can be looted from a Body or bought in a Shop (like in the Screenshot below), but you don”™t need any Maps for Info you can start also the Quest if you pick up any part of the Gear. There is not first and last Item, you can get them in any Order. You need to build and equip the Gear to get the Achievement

Below the Location of all (work in progress for the last two)Â Witcher gear sets