On this page of our guide to Sniper Elite 4 you will learn how to find the second document and how to get Panzerfaust in the course of completing the fifth mission of the game - Abrunza Monastery. Our guide shows you the exact locations of both these important items.
From the rock, in front of the radio station, you can easily get to the bunker (M5,8). Inside, there is the second document. Outside and inside the bunker there is no more than one enemy per each place.
In the part of the bunker, from where you can see the outpost, you can find a Panzerfaust - you can use it do destroy a cannon from a distance or eliminate a tank that can be found down the road. But I suggest not using this road to get to the monastery but get there from the center of the map.
Now, leave the bunker by using the ladder and immediately follow the narrow path to the town in the south...