This is the achievement earned for completing the first 'Act' of the game.
This Act comes in two parts. part 1 shouldn't be an issue, as it is heavily stealth based and is mostly a tutorial anyway.
Scene 2 may be a little harder. This scene triggers after the negotiations go bad. Use the green outfitting crates to top up ammo and grenades (do this at every opportunity for the rest of the game tbh). Go loud on your weapons, the suppressors will only reduce damage for the coming fights.
Prioritise taking out the rooftop shooters first. Let your team focus more on the ground troops. Use your TacMap often to see where the enemy are hiding. When it seems clear, send your team into the building to the right. Have them stack up on the door leading out to the left. Go back and up the stairs. Switch on Thermals and shoot the fire extinguisher. Clear the cafeteria-like room. Snake cam the door, select your teams targets. Eliminate the rooftop shooters and send the team in. Head in to the next building. Stack up on the door to the left, breach & clear or C4 it yourself for the ACEs. Snake Cam next door, tag targets, eliminate both. Climb the stairs. This is the trickiest part of the whole scene. Don't pass the glass windows, as there will be an explosion and many enemies will appear. Stay as far to the left as you can get away with, and have your team hide behind the glass. Prioritise the shooters on the balcony while your team deals with the ground troops again. When it seems clear, send your team to the left-most door to stack up. You're going for the other door beneath the balcony. Have them smoke and clear, and you deal with whoever you can that is distracted by their entrance. Regroup. Do NOT go round the corner in the next corridor. Either take cover and fire quickly and accurately, or send your team ahead. This final room with the bomb is all about hanging on. Tell Gabriel to defuse the bomb, and immediately take cover back in the corridor you came from. Throwing down smoke or shooting out fire extinguishers is also advised. Two Mounted Machine Guns will appear from behind rolling shutters. If you can, try line up the shot, change rate of fire to single and pop them quickly in the head. Eventually Six's team will storm the room from the opposite side, cleaning up any left overs and completing the stage.