app-myapp/modules/contact/contact-routing.module.ts

import { NgModule } from '@angular/core';
import { RouterModule, Routes } from '@angular/router';

const routes: Routes = [
  {path: 'list', loadChildren: () => import('./contact-list/contact-list.module').then(mod => mod.ContactListPageModule)},
  {path: 'detail/:id', loadChildren: () => import('./contact-detail/contact-detail.module').then(mod => mod.ContactDetailPageModule)},
];
@NgModule({
  imports: [RouterModule.forChild(routes)],
  exports: [RouterModule]
})
export class ContactRoutingModule { }