This paper proposes a new method for the motion planning for the assembly of components, using configuration space information, mobility potential and the components' CAD models. The proposed method plans a path and automatically sets the velocity and the acceleration for the assembly task. Automatic selection of velocity and acceleration, for the intermediate via points of the assembly path, generates a smooth trajectory and hence the system becomes continuous and faster. It also automatically adjusts the velocity for the assembly such that, the velocity is reduced as the assembly progresses. The path is planned in the reverse direction, i.e. from the assembled state to the disassembled state, using the potential variation method. The paper details the approach to determine the potential, path planning from assembled to the disassembled state, and automatic selection of the velocity and the acceleration for assembly, to generate a continuous trajectory. The concept is verified for the assembly of a rectangular peg and a rectangular hole.