You’re not going to learn much from a phone app. Specially programming.

“Learning apps” are mostly gamified gimmicks. If you never learned programming, you need a good book explaining the concepts of what you’re trying to learn, a computer, a project, and the internet to search when you get stuck.

I know it’s the boring answer, but this is one of those skills that it’s basically a lot of tinkering, exploration, and nose to the grindstone.