Back navigation button not showing up

Ionic Framework ionic-v3
1

I cloned the code using “ionic start myProjectName tutorial”, and changed the project according to ionic 3 , now , there is a file list.html , it has a button at header which opens side menu. i wanted to have a back button over there ,and removed the code for side menu opening. Expected that back button would automatically show up , but it did not happen, instead it shows header without any button with just title written

--> list.html
<ion-header>
  <ion-navbar> //a back navigation button was expected , but it's not there, 
    <ion-title>My First List</ion-title>
  </ion-navbar>
</ion-header>
<ion-content>
  <ion-list>
    <button ion-item *ngFor="let item of items" (click)="itemTapped($event, item)">
      <ion-icon name="{{item.icon}}" item-left></ion-icon>
      {{item.title}}
      <div class="item-note" item-right>
        {{item.note}}
      </div>
    </button>
  </ion-list>
</ion-content>