local monero network



with some people at my school and local science lab we want to make our own cryptocurrency. Mostly proof of concept and because it is just cool. Ofc we went with monero, but how would one go about creating such a altchain without changing a lot of the source code. I can barely find any documentation about that online. And I don't really want to change the block-parameters. So hwo do I tell my friends (and their machines) what out blockchain is so that they can mine our chain and not the real one.

Thanks :)