The construction of a Multilayer PCB involves several critical elements, including vias, pads, and through-hole plating. Vias are small plated holes that connect different layers of the board, enabling vertical signal flow and interconnections between traces. Pads act as the contact points for component soldering, facilitating the attachment of electronic components to the PCB. Through-hole plating ensures electrical conductivity between layers by coating the walls of vias with a conductive material.