<app-header></app-header> // Trying to navigate from this component
<router-outlet></router-outlet>
<app-footer></app-footer>

<a [routerLink]="['/signin']">Sign in</a>

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { FormsModule } from '@angular/forms';
import { HttpModule } from '@angular/http';
import { AlertModule } from 'ng2-bootstrap';
import { LayoutModule } from './layout/layout.module';
import { UsersModule } from './users/users.module';
import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { PageNotFoundComponent } from './shared/components/not-found.component';

@NgModule({
declarations: [
AppComponent,
PageNotFoundComponent
],
imports: [
BrowserModule,
FormsModule,
HttpModule,
AlertModule.forRoot(),
LayoutModule,
UsersModule,
AppRoutingModule --> This is the routing module.
],
providers: [],
bootstrap: [AppComponent]
})
export class AppModule { }

import { NgModule } from '@angular/core';
import { Routes, RouterModule } from '@angular/router';
import { SigninComponent } from './users/signin/signin.component';
import { PageNotFoundComponent } from './shared/components/not-found.component';

const routes: Routes = [
{ path: '**', component: PageNotFoundComponent }
];

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

export class AppRoutingModule {}

import { NgModule } from '@angular/core';
import { RouterModule, Routes } from '@angular/router';
import { SigninComponent } from './signin/signin.component';

const usersRoutes: Routes = [
{ path: 'signin', component: SigninComponent }
];
@NgModule({
imports: [
RouterModule.forChild(usersRoutes)
],
exports: [
RouterModule
]
})

export class UsersRoutingModule { }

import { NgModule } from '@angular/core';
import { HeaderComponent } from './header/header.component';
import { FooterComponent } from './footer/footer.component';

@NgModule({
declarations: [HeaderComponent, FooterComponent],
exports: [HeaderComponent, FooterComponent]
})
export class LayoutModule{}