Chapter 7 is an interesting part in LEGO Star Wars 7: The Force Awakens mainly because it is full of puzzles as opposed to having lots of action. Here is a small guide to tell you how to open the base’s door which is the first thing you have to do.
Opening the door is not that hard, but it can by annoying if you somehow miss something you failed to see the first time. I remember getting stuck because I didn’t know Finn was able to use his lightsaber in a specific room.
Before we talk about Finn, the first person you have to be is C3-PO. You want to open the door next to the question mark. He will release three Resistance Troopers.
After that be General Leia and press circle (B). She will tell them that she needs some help. Go next to the door and you will see four orange hooks. Press circle (B) and they will knock the boxes down. Jump on top of the boxes and jump again to pull the lever. Part 1 of the puzzle is done.
Part 2 is trickier and more time consuming. First, you have to turn right and head down. You have to be C3-PO again and there is a panel next to a question mark that will help you open the room with ice inside of it.
After you have done that, select Finn and head to the middle of the room you just opened. You should be prompted to press circle (B) for him to use his lightsaber. You should see a golden line for him to slice. This will enable you to build pieces.
If you do that, you can then push the ice block successfully outside of the door. After that, head outside and destroy the glowing mechanical parts. This prompts you to build something for BB-8 to use and he will control a crane.
Use BB-8 to move the crane near the ice block you just pushed. Then shoot at the ceiling and build a path for the blocks to make a path on the right side of the room. Use BB-8 again so that he can use the crane to pick up the ice block.
Once that is done, use the crane to move it near the top of the room (main door you want to open) which is north. You will need to shoot the ceiling again so the path can be created. If successful, the crane will put the ice block down.
Now you have to just push the ice block near the fire. To start the fire, just use BB-8 to control the panel by pressing circle (B). After that, build the last piece and jump on the lever to finally open the door!