In the first part of the mission, you will basically follow a tutorial. You are in no significant danger, but will need to follow the instructions.
Head to the ramparts, and snipe the two spotters. When they're down, head to the ground, and snipe the remaining spotter (ideal for a testicle shot the Charlie's Challenge achievement). Nest, destroy the heavy artillery - it may be destroyed in a single shot by aiming at the fuel tank on the bottom.
You get injured by the cutscene, but can use a medikit to recover from it.
Once you ascend to the mountains, you will need to destroy four Nebelwerfers (or take out their crew). These are most easily destroyed by a grenade, or by sniping its ammunition box. As always, sniping the artillery should be done while sound-masked.
When all four nebelwerfers are destroyed, a plane drops a stray bomb to open the path to the level exit.
- Get 8 kills using stealth takedowns. This objective may activate after you already performed one, which causes said takedown to be uncounted.
- There is another tower with a ladder you can climb near a Nebelwerfer (not the Sniper Nest), there lies the card.
- Found in the east of the map, near the Nebelwerfer. Its marked on the Map, you have to climb it and open the barred window. The game prompts: "Enter Sniper Nest" you have to open it to make it count. If you just climb the tower and do nothing else it will not count as found. You can see a Rifle with a helmet on top in the tower.
- After the cutscene bringing you to the second part of the mission, head to the right. You should find a defensive position, where you see "Letters to Martin".
- In the Tent, between two of the Nebelwerfers, inside stands a soldier, there you find "Survival Notes: Managing Heart Rate"
- From the sniper nest, look west towards the city. There is an enemy solider standing on the balcony (but if alterted, he may crouch or hide). Snipe him for the long shot.