Get down and defeat the guards. You will see a ladder leading down. Use it and defeat more enemies. Notice a pile of LEGO pieces. Make a ladder from them. Go up and push down a colorful statue. Compose a lever from LEGO pieces and take it to the left.
Using newly constructed mechanism you can rise a skull-elevator. As Indy, take a LEGO box and stand on the elevator. As child, use the mechanism to lift Indy up. Change your character back to Indy, get off the elevator and go to the right. Put the box in the correct place (look for the arrow pointing it).
Go to the left and jump above using whip. Defeat your enemies, take the torch and lit two places near the bridge. The child will be able to join you now.
As a child, use the hatch to get up. Use the lever and use the hatch again. Take the LEGO box, get down and put it on the green pad. Defeat the enemies and repair the statue. It will help you to climb up and go right.
Jump to the right using ropes. You will get to moving, big columns. You need to use brown bars to get from one column to another.
When you will reach the other side, defeat the guards and use simultaneously two levers. The gate will open.
You will be in a large room. Defeat the guards. Go left and destroy wooden barriers (screen). Use the mechanism and the statue will appear. Use the ladder to climb up but the foot-bridge will collapse. Jump to the other side using your whip. Go to the right using the statue. Use the lever.
Go to the right and you will notice two statues. Repair the first one using LEGO pieces and push it towards the wall. Then, pull the second statue. Change your character to the child and destroy LEGO pieces blocking your way to the hatch. Use the hatch, run to the right using the statues and use the lever to free Willie.
Now it's time for a boss fight. Hit him two times and he will start to run very fast. Concentrate on the fight with normal guards. After a few seconds you will notice that one enemy is dropping a black hat. Take it and use two, grey statues (while wearing this black hat). You will activate a fire which will hit the boss. Hit him few times and he will be eliminated.