You need to run the following command in the relevant project folder to generate the platform folders (Android, iOS, Web, etc). Some of the tutorials will have these already included, if needed.
flutter create .
https://pub.dev/publishers/funwith.app/packages
Tip 001 - Stretchy Header [ Video ] [ Code ] - Add a stretchable header to a Flutter application
Tip 002 - Staggered Grid View [ Video ] [ Code ] - Create a varying grid view in a Flutter application
Tip 003 - Popup Card [ Video ] [ Code ] - Create an interesting popup card/button effect