Welcome to the forum and the wonders of reloading. Everyone here just wants you to be safe while loading. Get a manual, almost any will do, and read the front part about loading procedures until you understand it. I like to use data from the manual produced by the bullet maker I'm using to load with. That being said, I always liked the procedure portion of the Nosler manual better than the Hornady one, as it seemed more straight forward to me. I also find a good reputable you tube video helps explain things too.
But the most straightforward manual I have is the Lee modern reloading 2nd edition. For the average loader, shooter, and hunter he really cuts it down to the basics. I think his best advice is to just use starting loads. Certainly until you have the hang of it, that's all you'll need. Starting loads are usually accurate, recoil less, are safer, and stress your brass and gun less. Follow the load recipe in the book to the T. Two of my deer loads I use now are just above starting loads. They are very accurate and kill deer just as well at most normal distances.
I'm using hodgdon Longshot in 9mm 40sw and 45 acp. Excellent accuracy and velocity with a very manageable recoil. 9mm has been loaded with Longshot in all bullet weights. As always do a proper load work up! Each firearm, pistol or rifle is different. Safety first no exceptions. Just recently had a close call but thankfully safe reloading practice saved my butt. Or face in this case.