Ask HN: How do I get started with developing an app from scratch?

I'm looking to try my hand at building a basic shopping list app on the side, to familiarize myself with the platforms used, so that I can better understand the experience firsthand. I've currently decided to get started with Android Studio and App Inventor, and I've got a reasonable level of beginner experience from both in the past evening. Are there any good tutorials out there that can help me learn further? Also, are there any better tools than these two out there? Cheers