Apple has created a handy guide on how to begin learning to create iOS apps. The new guide goes over what you need, where to begin and what documents you need to read to get going. Currently, I am working through the Apple documents and an Objective-C for dummies book found in Week 1 and to be blunt… it’s a lot of reading.
On your path of leaning, expect to be doing a lot of reading and a lot of coding to practice what you are learning. I have found that one of the keys to learning is trying to stop and understand the challenge that you just did. That could be creating a new struct, typedef or even something completely different. If you don’t understand why you are doing something the way you are being taught, then step back and try look at the bigger picture of what you are doing.