How to set splash screen time out on flutter

I am new to flutter and am kinda lost on how to set up a time to my splash screen so after this time it goes to the main screen. am using rive for the splash screen

import 'package:flutter/material.dart';
import 'package:rive/rive.dart';
void main() {
 runApp(const MaterialApp(home: SimpleAnimation()));
}
class SimpleAnimation extends StatelessWidget {
 const SimpleAnimation({Key? key, this.loading}) : super(key: key);
 final bool? loading;

 @override
 Widget build(BuildContext context) {
   return const Scaffold(
     body: Center(
       child: RiveAnimation.asset('assets/splash/splash.riv',
         fit: BoxFit.cover)
     ),
   );
 }
}

You can set 3 second time in initstate after navigate to which screen you want

class SplashScreen extends StatefulWidget {
  const SplashScreen({Key? key}) : super(key: key);

  @override
  _SplashScreenState createState() => _SplashScreenState();
}

class _SplashScreenState extends State<SplashScreen> {
  
  @override
  void initState() {
    // TODO: implement initState
    super.initState();
    
    // after 3 second it will navigate
    
    Future.delayed(const Duration(seconds: 3)).then((val) {
      // Navigation Here
    });
  }
  
  @override
  Widget build(BuildContext context) {
    return const Scaffold(
      // your code
    );
  }
}