Objective 1: Head to the vantage point
Right after the mission begins, equip the silenced pistol. In front of you there should be the first German soldier, leaning against a lamppost - kill him.
Go round the truck from the right and to the wall of the building [#1]. Wait for one of the walking soldiers to stand in line of fire and eliminate him.
Afterwards lean out of the corner - you should note a soldier standing nearby. If only the second one (patrolling on the left) isn't heading your way - eliminate him first. Hide behind the nearby crates and wait for the other German to notice the corpse - put a bullet in his head when he approaches.
Slowly move onwards, trying to stick to the train cars. At some point, a second train will arrive. Stand by the locomotive [#2] and use the deafening sound to get rid of the walking officer and the guard in the distance.
Carefully lean out from behind the locomotive - in the distance you should note a tower with a sniper on it. Once again wait for the locomotive to make a sound and shoot him.
Jump down from the platform onto the rails when the sound begins. On the neighbouring platform you will spot three Germans, out of which only one is patrolling. At this point you can either wait for him to come close enough for you to kill him with the silenced pistol, or try to lure him with a stone (rather risky, as you can lure the other soldiers as well). You can also shooting one (or more) as the locomotive makes a sound.
Go across the platform [#3]. Once again equip the silenced pistol - after you get onto some small stairs, you should note a walking soldier (facing the other direction) and a second one standing by the guard booth. Get rid of both of them silently. The further part can be played in more than one way.
Move further along the path - in the distance you will note a patrol. One of the German soldiers has a grenade with him. If you shooting skills are high enough, you can try shooting the grenade, eliminating all four of them at the same time. If something goes wrong, you always have the safety of being rather far away from them, so you shouldn't have problems with eliminating the enemies one after another.
Another way implies planting dynamite on the road (more or less as seen on the screenshot) and then shooting it (easier than the grenade, as the target isn't moving), therefore killing all four soldiers.
Objective 1: Head to the vantage point, part 2
Whatever tactic you use, the only one who will get "alarmed" is the sniper camping on the stone ledge behind the bushes. After getting rid of him, climb up the rocks to reach the vantage point [#4]. Right beside you will find an ammo crate. A cinematic will play.
Objective 2: Stop the convoy
The next objective is very easy - you need to stop the convoy, so that the Fuhrer cannot drive away and is forced to get out of the car. To do that, shoot the fuel tank of the first truck [#5].
Objective 3: Assassinate the Fuhrer
The last objective of this mission will start - you need to kill the Fuhrer. Your enemy will keep moving from one cover to another. You on the other hand will be constantly attacked by waves of German soldiers - most of the times they will stand in the same places. You shouldn't have any trouble with them. Just remember not to lean out too much, stay prone all the time and watch the Fuhrer move.
Also look out for the single sniper on the roof of the train station on the right.
If you have any problems with catching him, as some point a tank will appear - it's almost the end then. Try to stop the vehicle as fast as possible by shooting its tank.
Now you just need to watch the Fuhrer and wait for him to start running towards the train - don't let him reach it! Otherwise you will fail the mission. The sooner you kill him, the faster the mission ends.