Defeat your enemies. You need to find three boxes. Destroy the truck to do it, first you need to destroy its wheels and then the engine. Make a box from the LEGO pieces and take it on the green pad to the right.
Go to the right, get on the horse and jump on the higher platform (use U key while on the horse). Take the box and put it on the green pads.
Destroy the bars blocking the way into the cave. Enter it. As Sallah dig up gear-wheels near the green machine. Repair it, enter the lift and go to the left. Jump above the gap, climb up using the ladder and go outside. Take the box and put it on the little lift on the right side. Get down, take the box and put it on the green pad. Build a bulldozer from the LEGO pieces I destroy a blockade with it.
Now its time for a boss fight. Build a ladder from the LEGO pieces (look at the screen), go up, jump above the brown foot-bridges (they collapse). Push down the box and build a mine from the LEGO pieces. When the tank will ride on the mine it will loose some energy.
Two more mines are in the carts nearby. You need to act like a bait here. Stand near one of the carts and wait for the tank to shoot. Then escape and let the rocket hit the cart. Build two mines from two carts and destroy the tank. Boss will escape follow him.
Now you cant hit your enemy. Get on the horse and jump on the platform. When you will be on this platform, jump to the right. Go all the way to the right jumping above the gaps and above foot-bridges.
You will start to fight on the roof of the tank. Only thing you need to do here is to defeat all enemies and hit Vogel from time to time. Finally you will defeat him.