This electric/manual 3D wooden puzzle house operates with 3 Aa batteries and can also be manually rotated. It comes with 10 steel balls, including 5 spares to prevent loss. The pieces are securely connected using a traditional tenon and mortise method.To ensure smooth operation, do not overtighten the stairs and follow the manual for proper spacing. Use the provided stickers and measurements to align the pieces correctly, leaving some space between the collar and the board for ease of movement.For assembly, carefully read the instructions and pay attention to the direction of the boards. If you encounter difficulty pressing parts together, use a hammer for assistance.To remove a puzzle piece:1. Locate the connection point and gently press down.2. Once loosened, lift in the opposite direction.3. Gently shake up and down to easily remove the board.Always follow the assembly instructions for proper assembly and operation.