For this trophy, you have to follow the "A Model Citizen" quest line so you can reach the point where Vault 88 can start receiving settlers from the Wasteland. After interviewing the third settler, Clem, trade with him and give him a Pip Boy and a Vault 88 jumpsuit from the box near the entrance of the Vault. After you give him the Pip Boy and EQUIP the jumpsuit on Clem.