Sign up for a dev account and check out some of apple’s free resources while you wait, then do whatever the actually smart people on here tell you to do.
Turns out, you’re one of those people…
If you have prior knowledge of software development:
Read through the basics of Swift / Swift UI on the docs, find an idea you’re passionate about (preferably something simple, such as consuming an API), then honesty just try and build it.
Download Xcode and build a couple of small projects to get your feet wet. It is a really intuitive environment to code in. You don’t need to pay anything to learn.
No one can answer that but you.
Everyone learns things differently, so you might be fine with reading the manual, but someone else might need a classroom setting, guided training, etc.
Depends on how you learn. If you are asking this tho, that kinda implies you don’t know where to start. So grab a book and do some exercises. It might inspire you to make something real
Anytime anyone asks something like this, I only have one thing to say: Just do it.