I have a business idea that I think has potential, but don't know.where to start

First, I'd like to evaluate my idea without having it stolen. Maybe it isn't good enough for someone to steal, but ya never know. Second, if it is good, I'd like a business partner who knows how to build a business and is good with communication cuz I'm not exactly. I don't know if these are even the first steps to take though. Where should I start? The business idea has to do with reducing plastic pollution. It is to collect, clean and resell plastic packaging to product manufacturers, for reuse. Edit: thanks for all the advice. For now I'm going to work on launching my tiny, solo prop, very local, residential cleaning service. Using a wagon.