To initialize the Amplify API category you call `Amplify.addPlugin()` method. To complete initialization call `Amplify.configure()`.

Your code should look like this:

```dart
import 'package:amplify_api/amplify_api.dart';
import 'package:amplify_flutter/amplify_flutter.dart';
import 'package:flutter/material.dart';

import 'amplifyconfiguration.dart';
import 'models/ModelProvider.dart';

class MyApp extends StatefulWidget {
  const MyApp({super.key});

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  @override
  void initState() {
    super.initState();
    _configureAmplify();
  }

  Future<void> _configureAmplify() async {
    final api = AmplifyAPI(modelProvider: ModelProvider.instance);
    await Amplify.addPlugin(api);

    try {
      await Amplify.configure(amplifyconfig);
    } on Exception catch (e) {
      safePrint('An error occurred configuring Amplify: $e');
    }
  }

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      home: Scaffold(
        body: Center(
          child: Text('Home'),
        ),
      ),
    );
  }
}
```