how to set a starting page in a ionic project

I guess the problems is in your default route:

$urlRouterProvider.otherwise('/tab/login');

You have defined it depending from the abastract tab:

$stateProvider

  // setup an abstract state for the tabs directive
  .state('tab', {
    url: "/tab",
    abstract: true,
    templateUrl: "templates/tabs.html"
  })

and this is your login:

.state('tab.login', {
    url: '/login',
    views: {
      'login': {
        templateUrl: 'templates/login.html',
        controller: 'loginCtrl'
      }
    }
  })

the state name is tab.login which means it inherits from tab.

so your root is /tab/login.

this should be your tabs.html:

<ion-tabs class="tabs-icon-top tabs-color-active-positive">

  <ion-tab title="Login" icon-off="ion-ios-pulse" icon-on="ion-ios-pulse-strong" href="#/tab/login">
    <ion-nav-view name="login"></ion-nav-view>
  </ion-tab>

  <ion-tab title="Status" icon-off="ion-ios-pulse" icon-on="ion-ios-pulse-strong" href="#/tab/dash">
    <ion-nav-view name="tab-dash"></ion-nav-view>
  </ion-tab>

</ion-tabs>

as you can see your ion-nav-view name:

<ion-nav-view name="login"></ion-nav-view>

must match the one defined in your state:

.state('tab.login', {
        url: '/login',
        views: {
          'login': {
            templateUrl: 'login.html',
            controller: 'loginCtrl'
          }
        }
      })

You don't need to set the view's name here (login.html):

<ion-view view-title="Login" name="login-view">

Another thing I've noticed, you use the same name for two different views: tab-projects:

.state('tab.projects', {
      url: '/projects',
      views: {
        'tab-projects': {
          templateUrl: 'templates/tab-projects.html',
          controller: 'projectsCtrl'
        }
      }
    })
.state('tab.projects-detail', {
      url: '/projects/:projectsId',
      views: {
        'tab-projects': {
          templateUrl: 'templates/projects-detail.html',
          controller: 'projectsDetailCtrl'
        }
      }
    })

another thing has more to do with conventions. If you use for your views names starting with tab-, probably you should do the same for the login.

Here is a plunker with some of your code.

Change your app.js to

.state('login', {
   url: '/login',
   controller: 'LoginCtrl',
   templateUrl: 'templates/login.html'
})

and $urlRouterProvider.otherwise('/login');

If you place your login.html in correct folder then there is not going to be any problem.

I've been putting comments regarding your code, so let me formulate an answer with some steps you would like to follow

1:

You have a mess once you declare your controllers, try to follow a guide like this, at least declare your controllers/services/directives and so on in the same way, LoginCtrl and not loginCtrl and the other stuff with no capital as a first letter. It is just an advise my friend.

2:

.state('tab.login', {
    url: '/login',
    views: {
      'login': {
        templateUrl: 'templates/login.html',
        controller: 'loginCtrl'
      }
    }
  })

here something you need to check, the name of your view, you have login but

<ion-view view-title="Login" name="login-view">
  ...
</ion-view>

so change it to login only. And do the same in your abstract route.

like this

<ion-view view-title="Login" name="login">

And this so important

$urlRouterProvider.otherwise('/login');

which goes at the end of the $stateProvider. The otherwise method will always redirect to /login in case that any other route it's been matched

You should give a name to your <ion-nav-view> in your index.html template.

e.g. <ion-nav-view name="viewContent"></ion-nav-view>

Then, in your routes, you specify into which part of your app you want your template to be rendered, e.g.:

.state('login', {
    url: '/login',
    views: {
      'viewContent': {
        templateUrl: 'templates/login.html',
        controller: 'loginCtrl'
      }
    }
  })

this will render templates/login.html into the viewContent area. That's why UI-router is so flexible, because you can tell it exactly which parts should be replaced when routing.

If you don't need that flexibility, just write your routes without the views part and add controller and templateUrl directly to each state.

also your fallback probably should be $urlRouterProvider.otherwise('/login');

If you want to evaluate a success at login to show certain views should not be in the same state.

This should be true:

.state('login',{
  url: "/login",
  views : {
    'menuContent' : {
      templateUrl : "login.html",
      controller : "LoginCtrl"
    }
  }
})

$urlRouterProvider.otherwise("/login");

Follow the order as advice or guide on how to write their app.js

<script id="login.html" type="text/ng-template">
  <ion-view view-title="Login" name="login-view">
  <ion-content class="padding">
  <h1>lalalalala</h1>
  <div class="list">
     <label class="item item-input">
          <span class="input-label">Username</span>
          <input type="text">
     </label>
     <label class="item item-input">
          <span class="input-label">Password</span>
          <input type="password">
     </label>
  </div>
  <button class="button button-block button-calm" ng-click="login()">Login</button>
  </ion-content>
</ion-view>
</script>