Take Cover in the Yacht
Do not waste too much time for replenishing your supplies (two crates on the left). You have to be hurry because the armored vehicle will appear from the right, carrying enemy soldiers. Head to the yacht indicated by the game, stopping only after reaching its lower level.
Use such cover that you can observe your enemies' actions and eliminate them effectively. In the initial phase of the fight I strongly recommend focusing on quickly and safely killing mad knife man and elite soldier.
Later on, during the battle, focus on keeping an eye on your left flank, not letting too many opponents to attack you by surprise. Finally head to the captain deck located on the upper level, killing enemies there.
Prepare for more attacks. Look around the captain's deck searching for supplies (ammo and grenade crate). First attack enemies who will appear near dunes (screen above). You should hurry up because sandstorm will come soon, drastically reducing visibility.
After the sandstorm arrives, ignore distant targets and focus only on guarding stairs leading to the upper deck, not letting any enemy to get there. At the end of the battle, when the sandstorm is over, deal with rest of the opponents near the yacht.
Get to Lugo - Now!
Leave the yacht and follow Adams to the place indicated by the game (screen above). You have to walk through some linear corridors, where you won't encounter any enemies. After reaching the target, watch longer cut-scene, showing the death of your team-mate.
Get the Hell outta Here
When you regain control over Walker, you can act in two main ways. Shoot at civilians (screen 1) or shoot in the air or ground (screen 2). Do not try to walk between civilians or wait until they go away, because it would result in your death.
You can now go forwards. On your way you won't meet any new enemies, so you do not have to be careful. Look around for a kind of shrine shown on the above screen, with Intel Item. It is Konrad Effigy and can be found next to the metal gate. Once you kick the gate (left SHIFT), this chapter will end.