Start by making an app you want, then when you get stuck on a certain feature (eg: how to get GPS location?) then you google / stack overflow it. After completing multiple apps, you should have a long lasting grasp on multiple iOS dev concepts.
This is really the best way to go, it’s how I did it. Tutorials are nice but it’s too easy to watch them and go “yeah I get it” - Never actually implement what they’re saying because you convince yourself that understanding is all you need, but no implementation (because it’s ‘boring’) means no spaced repetition and you forget most of the material. Code, get stuck, google, implement, <= that cycle forces you to code…
Building something and struggling through the myriad of roadblocks seem to be the best way of learning anything programming related. I was a C developer, then started building web apps. I thought I was a good programmer through my C experience, but was amazed with how many technologies I had to learn to build a modern site. None of it was “hard” just a large quantity of stuff to learn and struggle through, one database or library at a time.