Hop in the car provided and drive over to the truck, then head over to the meeting point on Charge Island. Although the truck seems pointless, you'll have to arrive in it or you'll fail the mission. You'll then have to assault the boatyard and kill everyone there.
The problem is, Phil goes with you and has a nasty habit of charging into enemy fire. If he dies, you'll fail the mission. The key to keeping him alive is to take out to kill all the enemies up front except one. As soon as all the close enemies are dead Phil will move forward, but if one is alive he'll hold his position. This lets you take out the enemies in the back, so Phil doesn't charge in and kill himself.
Watch out for the explosive barrels inside the boatyard. For this reason, driving the truck into the building isn't recommended. Conversely, you can just shoot the barrels to take out any enemies near them. Watch out for enemies up on the catwalks as well, and don't miss the Body Armor by the cable spools on the left side.
When you get to the other side of the building, Phil will hop into a boat, so you should hop in the other one there. Phil will take off, so pull into position about four boat lengths behind him. You'll be attacked by two speedboats, so shoot the driver before he can harm Phil. Try to wedge yourself between Phil and the enemy boat. You don't have to stop both boats; they'll give up after you get far enough away. Pull up to the dock on the other side, get out, and walk into the marker to end the mission.