Many clubs around me operate their own referee “pools” who are appointed to games under the club structure within their respective leagues. And many of these have a referee coaching structure or proper mentors in place too.
They work hand in hand with the youth leagues here, so it can be a good option to get started.
I’ve looked and you’re a long way from me, so I can’t suggest any that I work with, but the critical thing is you don’t need to affiliate with the club per se. If you work with them just let appointing officers know you’re in said club’s pool.