Need some advice for a robot-building system

I am currently working on a game that involves the creation of robots and I’m tasked with the development of the system that allows the player to actually build them. I’m having a hard time trying to wrap my mind around a way to efficiently develop this system. My original idea was to have a base robot character class that has a pointer to an array of joints that the components of the robot could be attached to, then I could just extend that class with blueprints of more specific robot character classes. I’m having a hard time implementing that. I would love some advice on how I should approach designing this system. To summarize: the system would allow a player to select a part, this part would then be attached to a joint that the player selected and would become part of the robot that the player controlled.