var app = angular.module('plunker', ['ngMaterial']);

app.controller('MainCtrl', function($scope) {

  $scope.back = function() {
    if ($scope.tabIndex > 0) {
      $scope.tabIndex--;
    }
  };
  $scope.next = function() {
    if ($scope.tabIndex < 2) {
      $scope.tabIndex++;
    }
  }
});
<!DOCTYPE html>
<html ng-app="plunker">

<head>
  <meta charset="utf-8" />
  <title>AngularJS Plunker</title>
  <link rel="stylesheet" href="style.css" />
  <link data-require="angular-material@1.1.0" data-semver="1.1.0" rel="stylesheet" href="//ajax.googleapis.com/ajax/libs/angular_material/1.1.0/angular-material.min.css" />
  <script data-require="angular.js@1.5.x" src="//cdnjs.cloudflare.com/ajax/libs/angular.js/1.5.11/angular.min.js" data-semver="1.5.11"></script>
  <script data-require="angular-animate@1.5.5" data-semver="1.5.5" src="//code.angularjs.org/1.5.5/angular-animate.js"></script>
  <script data-require="angular-aria@1.5.5" data-semver="1.5.5" src="//ajax.googleapis.com/ajax/libs/angularjs/1.5.5/angular-aria.min.js"></script>
  <script data-require="angular-messages@1.5.5" data-semver="1.5.5" src="//ajax.googleapis.com/ajax/libs/angularjs/1.5.5/angular-messages.min.js"></script>
  <script data-require="angular-material@1.1.0" data-semver="1.1.0" src="//ajax.googleapis.com/ajax/libs/angular_material/1.1.0/angular-material.min.js"></script>

  <script src="app.js"></script>
</head>

<body ng-controller="MainCtrl">
  <div class="md-padding" ng-cloak>
    <md-tabs md-no-pagination="false" md-selected="tabIndex">
      <md-tab label="tab1">
        tab1 content
      </md-tab>
      <md-tab label="tab2">
        tab 2 content
      </md-tab>
      <md-tab label="tab3">
        tab 3 content
      </md-tab>
    </md-tabs>
    <md-button ng-click="back()" class="md-raised">
      Previous
    </md-button>
    <md-button ng-click="next()" class="md-raised">
      Next
    </md-button>
  </div>
</body>

</html>
/* Put your css in here */

.md-tab {display: none;}