Select the "Extras" option and load a previously saved game file. Select "Game Secrets" > "Enter Code". Enter one of the following symbols in the Alethiometer in the order, top left, bottom left, and top right. The corresponding featurette will become unlocked at the "Featurettes" option at the "Extras" menu.
After you chase the boy and he tells you how to go to the docks, go there. Collect the marbles and wall forward to the beam, then jump on the beam and go to the end. You must go to the end of the beam. Do not jump when the action light first appears; instead, go all the way to the end of the beam or you will fall into the water. After you have jumped on the train, use your insight to see where to jump next. Use your Sloth form. Once you land on the box, turn back to the left and jump to the next sloth swing, which will take you to the next level up. Collect all the items, then use your Insight on the two birds before you get too close and they fly away. Use Sloth or Bird form to jump down to the pillar. In Bird form you can control where you land easier. When you get to the second pillar you can either collect the items to the left bu jumping from crate to crate or by just climbing up from the second pillar and then changing to Sloth form. Use Insight to see where to jump next. When you leave the sloth swing, you will land on a beam and go to a second beam halfway across the last one. Exit from the second beam to the train. Go to the end of the train by the crane and collect the marbles. Then, climb back on the train, use Sloth form, and jump on the box. Use Insight for sloth swing. Jump to the sloth swing towards the water and go to the flat boat. Next, jump box to box until you get to the cat climb. This can be difficult; go to the edge of each box and wait until it floats toward the next box. It may not look like much, but you will miss if you are not careful. At the cat climb, go to top and collect the last orb, then go to the left to collect the other three. Slowly go down where last orb was located, then drop to another balance beam. Go to end of the beam, jump off, and collect three marbles behind a train. Go toward the building and collect the item behind the train on the left, then to the area where you can see a train in the water and jump down. Get on the box, then jump to sloth swing to the first train. Jump to the right to the sloth swing and you will go to a roof. Jump down to collect the item on the second train, then go back to the train in water. Jump back on the last train. Jump on the box and walk a board. Pan will gnaw through the rope then you need to jump from box to box. They will sink so you need to be quick. Use Bird form and quickly glide from one box to the next, as the boxes will sink otherwise. You will end up on another dock. It is fairly easy after that. Collect the items on the box and train boxes, then fight the guards. Collect more items. You must distract the guard in the yard. Throw an item at the bell. Go in the yard. The guard will not bother you. Gather items as desired. Climb on top of the building.