Tab Panel Implementation?

Im trying to implement a basic tab panel like the guide. But no where does it say where im supposed to put it. I generated a new app through the cmd but when I edit my app.js file and place my code under the launch in ext.application nothing happens. I know im missing something basic. This is what it looks like though. Im sure its some stupid reason why I cant get it to show

HTML Code:

// Destroy the #appLoadingIndicator element        
Ext.fly('appLoadingIndicator').destroy();
       
 // Initialize the main view        
Ext.Viewport.add(Ext.create('eXPy.view.Main'));                

Ext.create('Ext.Carousel', {
        fullscreen: true,
        defaults: {
        styleHtmlContent: true
        },
        items: [
        {
            html : 'Item 1',
            style: 'background-color: #5E99CC'
        },
        {
            html : 'Item 2',
            style: 'background-color: #759E60'
        },
        {
            html : 'Item 3' 
       } 
       ]
    });