How to add new list when I click on the current list

gist.dart

import 'package:flutter/material.dart';


void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      debugShowCheckedModeBanner: false,
      home: Scaffold(
              body: UploadDoc(), 
        ),
      
    );
  }
}

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

  @override
  State<UploadDoc> createState() => _UploadDocState();
}

class _UploadDocState extends State<UploadDoc> {
  final List<Map<String, dynamic>> listSelection = [
    {
      'id': 0,
      'header': 'Muat Naik Surat Rasmi Permohonan',
      'title': 'Muat Naik Surat Rasmi',
    },
    {
      'id': 1,
      'header': 'Surat Lantikan Peguam',
      'title': 'test',
    },
    {
      'id': 2,
      'header': 'Surat hubungan peguam dan pemilik daftar',
      'title': 'test',
    },
  ];
  final List<Map<String, dynamic>> selected = [];

  // 'icon': const Icon(Icons.add_circle_outlined),
  int counter = 0;

  @override
  Widget build(BuildContext context) {
    if (selected.isEmpty) {
    selected.add(listSelection[0]);
    }
    return Scaffold(
      appBar: AppBar(),
      body: ListView.builder(
        itemCount: selected.length,
        itemBuilder: (ctx, index) {
          return Column(
            children: [
              Container(
                  width: double.infinity,
                  height: 30,
                  color: Colors.grey,
                  child: Row(
                    mainAxisAlignment: MainAxisAlignment.start,
                    children: [
                      const SizedBox(width: 10),
                      Text(listSelection[index]['header'],
                          style: const TextStyle(
                              color: Colors.black,
                              fontWeight: FontWeight.bold)),
                    ],
                  )),
              ListTile(
                leading: const Icon(Icons.add_circle_outlined),
                title: Text(listSelection[index]['header']),
                onTap: () => _addNewUploadDoc(),
              ),
              const Divider(thickness: 1)
            ],
          );
        },
      ),
    );
  }

  void _addNewUploadDoc() {
    setState(() {
      if (listSelection.length > selected.length) {
           selected.add(listSelection[selected.length]);

      }
    });
  }
}