1) Buy a handgun
2) Learn how to shoot it fairly well
3) Take a holster-based course, like the required Black Badge course for IPSC, or equivalent for other forms of competitive shooting
4) Go have fun!
That's basically it. Each step can be a category in itself, but those are the key milestones.
Briefly, say you want to compete in IPSC, then the Shadow is a great gun to start with. Or if you're thinking IDPA, then a lighter gun may be what you want. Or 3-gun, maybe you want something else. Or if your eyes are old like mine, I'm thinking of buying a gun with an optic...... Before all that, it is often recommended to buy a .22LR pistol to learn fundamentals without developing a flinching habit. See? Each step is a discussion.
Once you have bought the gun you want for whatever you want to do, now you need to learn how to shoot it. Think of that buzzer going off to start shooting, as a giant brain-fart signal. lol! Shooting under pressure or from strange positions can make you shoot poorly, or even unsafely. So it's good to have a decent set of skills before you move to holster use and competition. I really like Murray Gardner's guideline of being able to put 9/10 rounds on a piece of 8.5"x11" paper at 20 yards, slow fire. Once you can do that, then you can take his Black Badge course.
Now go buy some gear, (belt, holster, etc) for what you want to do. Or better yet, see if you can find a helpful club and/or friends who can let you borrow the gear to try this all out before spending a bunch of money. I did that for a friend recently. So, go make friends!

Once you get some gear and pass whatever holster safety course you need for whatever you want to do, then go have fun.
Be sure to check out a variety of clubs near you to see what they offer. Some may offer shooting events that don't need a holster. Try as many of these out as you can. You never know what you may like.
