The first thing you should do is spend several years working at the sort of magazine you aspire to publish. Learn how it's done, and what's required.

That will be a full time job and won't pay you anything. So you'll need another full time job to earn your living; and it had better pay extremely well because you'll need a few tens of thousands of dollars to set up your magazine. And you are extremely unlikely to ever earn any of that money back, so you'll need to keep your well-paid job when you launch your magazine.

It's very hard work, earns little or no money, and you'll get little thanks for it. I have several friends who have started their own magazines and done well with them, all things considered: but they've burned out very quickly, and have struggled. Make sure you know what you're getting yourself into before you go ahead.