https://docs.flutter.dev/get-started/install/linux Doesn't seem to be packages for anything really so you've gotta download this precompiled version and add the extracted flutter/bin to your path.

doctor

flutter doctor

This checks if your flutter install, android development install, and so on are all working.

create

flutter create projectname

flutter run

This should open your app on a plugged in phone. Press r to hot reload. Press R for a hot restart.

Declare the packge in your pubspec.yaml and then fetch it with:
flutter pub get

dependencies:
  flutter:
    sdk: flutter

  shared_preferences: ^2.0.13