The map immediately summons all five objectives. However, from the start of the map, there's a chance the enemy/AI might already see you and start shelling. Therefor, waste no time and start attacking the two closest enemy settlements. Expect two fierce battles!

Next, aim for the settlement in the middle. Beware you'll become within heavy enemy/AI artillery range from the north and northwest. Then, when you possess three settlements, go for the fourth and fifth objective.

If a frontal attack is giving you headaches, you can opt for going through the desert in the west and attack from the side.