I'd just start by going to a gym. It can get overwhelming when you are new because everyone swears that how they do something is the end all be all way to do something(Ironically I'm gonna tell you some stuff I would do). My only tip would be remember to shadow box a lot!
Remember that during shadow boxing you are fighting a simulated opponent so be mindful to work on offense as well as defensive and evasive maneuvers. Imagine yourself fighting taller people, shorter people, runners, aggressive fighters, and in close quarters. I find it helps me to watch other people in the gym. Take a look at how they move around and try to simulate what you like as best as you can. If you like how someone hits the bags or how they pivot when they throw a certain punch try to add it to your repertoire. You will eventually gain a style that comes to natural to you.
For now just go to a gym do whatever they tell you, and the rest should come natural. Remember that boxing is an art!