How to use own code for another project?

I have written C code for general purpose parallel communication and shared it on github. Now I want to use this code to write Python libraries for several different chips that use parallel communication.

I would like to know what is the most github-ic way to do that? It seems that forking would be the best solution, but I cannot fork my own work. I was also considering branching, but I honestly do not understand the concept. (And when I update code I simply replace the old code with a new one.)

I understand programming, but I simply don’t understand github and its concepts, despite all documentation on the web.

Thanks for your suggestions.