nest router-outlet

app-routing.module.ts

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

import {DashboardComponent} from './dashboard/dashboard.component';
import {LayoutComponent} from './dashboard/layout/layout.component';
import {HomeComponent} from './home/home.component';

const routes: Routes = [
  {path: '', redirectTo: 'dashboard', pathMatch: 'full'}, {
    path: 'dashboard',
    component: LayoutComponent,
    children: [
      {path: '', component: DashboardComponent},
      {path: 'home', component: HomeComponent}
    ]
  }
];

@NgModule({imports: [RouterModule.forRoot(routes)], exports: [RouterModule]})
export class AppRoutingModule {
}

app.module.ts

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';

import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { DashboardComponent } from './dashboard/dashboard.component';
import { HomeComponent } from './home/home.component';
import { LayoutComponent } from './dashboard/layout/layout.component';

@NgModule({
  declarations: [
    AppComponent,
    DashboardComponent,
    HomeComponent,
    LayoutComponent
  ],
  imports: [
    BrowserModule,
    AppRoutingModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

layout.component.html

<p>
  layout works!
</p>
<router-outlet></router-outlet>