How do I START a 3d printing business

So I want to start a 3d printing business. I think I’m going to try to start on Etsy and after I get a few more printers I’m going to start trying to find some businesses that I can print stuff for. What is some advice for STARTING a business. I have watched many videos talking about how to make your operation more efficient but I have no idea what to do to get it off the ground initially. Any advice would be appreciated