That’s all really good advice. And much appreciated. I’ll just add a few things that have helped me when starting and continuing my campaign.
An Alternative for Mapmaking is Inkarnate. That’s what I use. And for people who tend to do better learning from videos, and even experienced DMs I highly recommend Matthew Colville’s Running the Game series on YouTube. Also his campaign diaries are really insightful as he goes through his process of decision making and session flow that you can watch after his Livestremed game.
I think the the most important advice I can give someone that is interested in running a game is you do NOT need to flesh everything out before hand. Just start with Session 1. Start with 1 town. Start with fleshing out a few NPCs in that town. I call it the magnifying glass approach. When the session ends know where your players are heading and move your magnifying glass to flesh out that area. And keep doing that as the campaign progresses and eventually you’re world will be a living breathing thing.
In my experience DMing is like a magic show of smoke and mirrors. All you gotta do is give your players enough to make things interesting and they’ll fall for it everytime.