Speak with Sheldon, then get into one of the helicopters and fly to the next objective. You need to take out the military ships which means you should stay moderately low to the ground. This makes it easier to hit the ships with your missiles. Keep an eye out for the enemy choppers in the area, as well as the SAM site and the ships chasing Mario and Dimah.
Once you’ve taken down all of the enemies in the area, get out of the chopper and head down to the boat below. Take the boat around the coastline as you check in on a few informants. You pass through a minefield as you head toward the next marker, but you won’t have to worry about any enemies.
Head over to the small island once you reach the second site, then turn around as you make your way to the final destination. Meet up with Annika and Teo to have a quick conversation, then take out the enemies that attack to complete the mission.