If you go with a union there is usually a training program. Otherwise, you work as an assistant to a contractor. Journeyman is a union word to describe an expert. My husband is a general contractor and a solar contractor. It was all basically self taught with a few classes here and there. (And an issue or two of Time Life~) He passed the exams at the contractors licensing board, got the appropriate business licenses and insurances and had some good bread and butter clients. He has a few guys who work for him. Maybe one (The painter) could pass the test and get his own painting contractors license, but I don’t think he has the financial sense to manage a business.