How to create my own robot?

First of all, I will clarify my issue. I want to use a custom robot to complete some tasks instead of the ABB robot. Currently, I have successfully constructed a custom robot using geometric shapes, but I am unable to effectively control it. I cannot add a controller to it. Using the controller wizard provided by the RS software, it prompts me with "This combination is not supported" or only allows me to select its own robot controller (of course, it cannot be used for the custom robot)
Thank you for your reading and assistance. Also, I extend my sincere regards.