Blazkowicz must operate the tunnel glider inside the sewage tunnels to access the Nazi stockpile in the catacombs.
From there he must steal a train in order to get on-board a nuclear submarine. The first part of Chapter 10 takes place in the sewers where theres a lot of water and no commander to reveal the collectibles on the map. Because of the water it is very hard to find them without knowing where to look and when to look.
Follow the next Wolfenstein: The New Order guide in the same order as below if you dont want to miss any of the collectibles in Berlin Catacombs.
Chapter 10 Mission Details
Im in the sewers of Berlin. Air is humid and rank down here. Smells like something crawled inside Hitlers ass and died in there. Carolines got this great plan to get me on-board a nuclear sub.
First, I need to find a way into the catacombs and steal a train.
Enigma Codes: 8
Health Upgrade: 1
Wolfenstein: The New Order Chapter 10 Collectibles Guide
Gold #1 (Gold Book)
Use the tunnel glider until you reach a locked sewer gate. Cut the chain and after you get through the gate exit the glider and search for a hole in the rocky wall on the left side.
Get inside and swim until you reach the surface. Move a little further to find a secret room.
The first Gold piece is on the wire coil next to the mattresses.
Letter (Ingrids Letter)
On the other side of the mattresses is the Letter collectible.
Enigma Code #1 (Piece 3:2)
The first Enigma Code piece is in the same room, on the table in the corner (next to the hole).
After you move the giant waterwheels you need to reach a platform to raise the water level. Before doing that jump in the basin where you cant move your glider yet and search for a safe on the bottom of the basin.
Crack it to get the Health Upgrade.
Next, use the ladder near the basin to reach the platform above. As soon as you enter the room with the switch look for the sewer Map on the oil barrel thats on your left side.
Enigma Code #2 (Piece 3:3)
Use the switch to raise the water level the jump in the basin and swim to the right side of the platform to find an area adjacent to the room with the switch. Theres a ladder opposite to the ladder you used to reach the platform, but its broken and thats why you have to raise the water level beforehand.
The Enigma Code is on a box inside the room.
Gold #2 (Gold Ladle)
Jump over the railing and swim through the opening of the waterwheel on the right hand side (you can get your glider to move faster).
As you pass through the waterwheel you should see the Gold collectible on a ledge to your right.
Gold #3 (Gold Snake)
Turn around and go through the tunnel.
In the right corner of the area is another tunnel that is blocked by metal debris on the other end. In the debris you can find the third Gold piece in Chapter 10 (the tunnel is really dark, but the collectibles stands out as it glows).
Gold #4 (Gold Lantern)
Exit the tunnel and head towards the collapsed wall / structure. Turn left to see a submerged room that is illuminated (the door is opened). Get inside to find the Gold collectible.
Enigma Code #3 (Piece 3:4)
Now that the water level is higher you can dive in the next section of the sewer. On the bottom there are two mines hold in place by chains.
Cut the chain of the first one thats in front of you and then of the second one thats a little to the right. The mines follow the flow of the water and they explode when they encounter obstructions, thus clearing the path for you. After the first mine explodes go up the stairs to the left.
The Enigma Code piece is on a box in the corridor on your right.
Enigma Code #4 (Piece 3:5)
By now, the second mine should have cleared the path, so jump in the water and swim until you cant go any further. The only way to get out of the water is by using some stairs (left side). As you go up the stairs you can see a shelf in front of you, next to a door. The fourth Enigma Collectible is on the shelf.
Enigma Code #5 (Piece 3:6)
Unlock the door with your laser and jump through the hole in the floor. Follow the path through the pipe and after you climb up the ladder look to your right to see the Enigma Code thats on the shelf.
Gold #5 (Gold Lunula)
From the previous collectible head in the next room. The fifth and final Gold piece in Chapter 10 is on the ground next to a metal crate.
Enigma Code #6 (Piece 3:7)
After you take the elevator to the train station grab the yellow box thats in front of you because it is the Tesla upgrade for the Laserkraftwerk.
Head right and follow the leftmost train tracks to the platform on the left. The platform is slightly elevated so go beneath the first laser charging station, just under the stairs, to find the Enigma Code piece.
Enigma Code #7 (Piece 3:8)
Climb on the platform and head inside the small room below the control room. The Enigma Code collectible can be found on the shelf in the room.
Enigma Code #8 (Piece 3:9)
To get to the control room you have to raise a gate, but when you do that you are attacked by a supersoldier. After you defeat him raise the gate and go upstairs to the control room.
Before pressing the button grab the final Enigma Code collectible thats on the console on your right.