Far Cry 5 - Explosive Surprise Trophy Guide / Achievement Guide - Sabotage 5 vehicles in a way that kills an enemy (Campaign only) [Silver]

First you must buy the "Saboteur" Perk. It costs 7 Perk Points.

Now stand on any road by a fast travel point, in a hostile territory, and wait for an enemy car. I picked the fast travel point "Red's Farm Supply" in the middle of John's region. Enemy cars always spawn there within a few seconds, but any other fast travel point works too.

When the enemy car comes, wait for it to stop and shoot the driver. Now stand by the driver's door and sabotage the hood of the car (Hold Square on PS4 / X on Xbox One). The remaining enemy can't hit you when you stand on the side of the hood rather than the front. It takes a few seconds to sabotage it. Once done, crouch around the car. Make sure the enemy stays nearby (he usually takes cover behind the car if you crouch).
It takes 10 seconds for the car to explode. It has to kill the enemy (he has to be very close to the car). When the enemy is dead, open the map and travel to the fast travel point again.

Now stand on the road again and wait for the next car. One usually spawns within 10-15 seconds after reloading the fast travel point.
Rinse and repeat. Always shoot drive, sabotage hood, let it blow up, use fast travel, repeat. After 5 successful sabotage kills you earn the trophy.