YouTuber Tom Scott created a 15-part series on how to create a smartphone app – not really the tech details, more like the foundations and basics you need to know. He spends a lot of time telling you why you probably shouldn't make an app and why you will regret it if you do. Tech support, for instance, is a nightmare.
In the first episode, he interviews the Adrian Hon, creator of Zombies, Run!, which has been downloaded over 4 million times.