You will receive this trophy once you complete Order No. 14 where you deliver aid to Port Knot City. Upon arrival to the first delivery terminal after you deliver your cargo, you will be prompted to leave to the dock to depart to the next area. You will meet the creepy Higgs for the first time and have to fight your first boss, which is a BT Catcher, that he conjures up. Use hermetic grenades to kill it until it crystalizes and vanishes. Once the mission complete results screen finishes your stats the trophy will unlock.
You will also attain another trophy during this mission in: