ELEX

this is one of the main quests of Chapter 1 and becomes available very early in the game.

you need to find Ray the person who stole your armour. He is holed up in Sandy Pines Motel. North of Goliet where the desert blends into the green. To pinpoint his location, scroll to the mission and press to show on the map, this will pinpoint his location. This feature will be your new bestfriend as the map his huge and the quests scattered.

All you have to do is make your way to Ray, when you approach a cutscene will play. Ray is also one of your companions, but the achievement will unlock after the cutscene. Due to ferocity of the local wildlife its best if you either wait until you are a higher level and more familiar with the games mechanics or take Duras with you as a companion.

This is part of story progression. You need to make it to the motel area in the middle of the map and talk to an important NPC who can be a follower.