Method 2: Flutter - Cross platform App development (meaning it can run on multiple platforms: android, iOS, windows).
Step 1: Learn Dart
Dart is aprogramming language used in flutter. Which is currently the best toolkit for cross platform app development.
Here you’d learn essential Object Orientated Programming (OOP) concepts: basics and syntaxes, data types, variables, classes, conditional statements, loops etc.
Tutorial you can use:
youtube.com/playlist?list=PL…
Step 2: Learn Flutter
How to set up a flutter app, tools, widgets, packages etc
Tutorial you can use:
youtube.com/playlist?list=PL…
Method 3: Cross Platform Apps with react native.
This is best suited for those who already do web development and want to migrate to app development.
This would be the easiest transition.
Step 1: Learn web dev - Html, CSS, JavaScript
Step 2: Learn react - components, props, state management, hooks etc
Step 3: Learn React native- building cross platform mobile apps.
You can just look up tutorials of these on google/YouTube.