Use the hopping bricks to construct two Stormtrooper dummies then destroy them both to earn your red brick. Jakkuįind the floating red brick in the corner near the shop stand, then destroy all of the LEGO objects in the village to find hopping bricks. You can then build a scaffold out of the cage and use it to climb around and get the red brick you see behind.
Use a short character like Wicket or BB-8 to get up on the platform, then use a strong character like Chewbacca to pull the lever and push the cage down to the ground.