A lot of naive young guys jump into business knowing relatively little. Some succeed through dumb luck, many fail. This way of doing things is often harder than knowing something. From my point of view, an easier way would be to get a job with someone in the business you want and work for him for a year learning as much as you can. If you are a quick study (i.e. learner) you might get promoted in this business and either learn a lot more or and/or decide to keep working for someone else.
Were you to go to school, they would teach you to make a business plan - come up with a list of what you will need (equipment) and what amount of money you will need until your business becomes profitable. You also have to figure out where your customers will come from and how much you will charge for your services.
I went into business as a handyman, working for $3.00/hour back in the early 70's. I could barely make ends meet, and decided to become an electrician mostly because they were making good money at the time, and carpentry tools were much more expensive than electrician's tools. I asked a friend how I could get licensed, he lied for me and said I'd worked for him for a year, and I listed that and my engineering degree on my City's application form. I took the test, passed, and was a licensed contractor - with no work, no income and basically no knowledge of how to be an electrician. I called the local union and back then you had to have family in the union or pay someone off (I was pretty dumb). They basically told me to do something that was anatomically impossible. (Years later I had the good fortune to tell several business agents my story and to get their carcasses off my job - and that if I were to join the union at that point when they wanted me, I'd be taking a huge pay cut.). I called my friend again (he was an electrical engineer), he wanted to sell equipment and not install it and I did the manual work and he sold the equipment. Over some time, I built a reputation for excellent work, never advertised, and ended up with more work than I could handle - but it took a while. It would have been easier for me had I gone to work for an established company for a year or two and then gone out on my own.