Trevor is the only character that can play this mission line.
There are no objectives for this mission. Simply go to the website Josh texts you with. Visit the website and go to the “Find Properties” map. It will open up a map of all the properties you need to visit. Click on each one and click “Get Directions” to have a waypoint marker added to your minimap. All that’s left to do is visit each house and deface the sign outside. Shooting them, running them over, throwing explosives. Whichever sadistic method you want to use is fine.