⬢Put the plastic part with the metal part on the bottom face of the electronic board.
⬢Modular Bed PCB Shield
The Modular Bed PCB Shield should be on the top of the plastic part
The plastic and metal parts are not attached to each other. You have to hold the parts.
⬢Attach the board back on the heatbed. Secure the board with four M3x10t screws.