Almost immediately you will be attacked by enemies. Defeat them and go to the right. Destroy LEGO pieces near the cart, take the LEGO piece and put it on the trails.
You need two more pieces. Go all the way to the right and dig up LEGO pieces (if you dont have a shovel, you will find one destroying tool boxes nearby). Take the LEGO piece back to the trails. You need one more piece.
Go back to the right and push the cart. It will destroy the wooden blockade. Compose the last trail piece from LEGO and carry it to its place.
Go back to the place where you have started the level. Take the blue box I put it on the green pad. As Indy use whip on the highlighted place, climb up, take next box and put it on the second, green pad. Repair the crane with LEGO pieces.
Enter the crane and pick up big box with it. Drop the box on the elevator to the right of the crane. Change your character to Marion, jump on the elevator and on the platform. Go strait ahead and jump on the cart. As Indy, push the cart with Marion to the right side. As Marion jump from the cart to the right and make a rope from the LEGO pieces. Indy will join you. Jump on the rope and go through. Defeat your enemy and go up the stairs.
Go to the right and you will reach enemy camp. Defeat soldier who is throwing grenades and take his hat. While wearing the hat, knock to the window near the gate. The gate will open. Go through it.
Defeat your enemies and destroy everything on your left side. You should find a shovel. Take it and dig up a box you will find a key in it. Notice two towers to the right near the gate. As Marion (or Indy, thou it is easier to do all this staff with Marion) jump to the left tower and hang on the rope. You will see LEGO pieces compose a lever from them and use it.
As you will be using the mechanism, the rope will move towards the right tower. Stop turning the mechanism when the rope will be in the middle and jump to the right tower using this rope. Use the key on the second mechanism, jump on the second rope and into the third tower. Use the lever there and a LEGO piece will fall down.
Build a fan using this LEGO pieces and put it on one side of the gate. You will build the second fun from the LEGO pieces to the right of the gate. Put it on the right side of the gate and go through.
Its time for a boss fight. Take an anvil and let the boss hit you. He will lose one life-heart. This is the only way you can hurt him.
You will notice, that a truck with more enemies will arrive. Enter the plane and using its guns destroy your enemies and the truck. From the LEGO pieces you will build next anvil. Take it and let the boss hit you. Next truck will arrive repeat all actions to finally kill the tough guy.
You will start on the roof of the truck. Wait a while for the next truck to arrive and jump on its roof. Defeat you enemies and wait for the driver to get on the roof. Kill him and enter the truck. Hold the U key to accelerate and to get closer to other trucks. Get on the roof and kill more enemies. Enter next truck and accelerate. Repeat this as long as you will notice a truck with golden ark. Jump on it and defeat enemies. After that, enter the truck and accelerate to hit the escaping car.