In this chapter, we discuss the practical aspects of hardware and software designs of the M-TRAN system. In principle, behavior of lattice-type modular robots like M-TRAN can be understood to some extent without any physical experiments, instead investigating the algorithm itself, or making computer simulations. Also, motion control of a robot can be investigated without a real machine, if precise dynamics of the robot is modeled. However, methods and algorithms established on abstract models are meaningless unless they are physically realized as real robots and machines. When building a self-organizing mechanical system, we need to consider various issues of many different areas such as mechanical engineering, control engineering, robotics, and systems engineering. In this chapter, we introduce topics we studied while building the M-TRAN system.