Problems With Viewer once Leaving SandCastle mainly because of require (New Cesium User)

CesiumJS
1

Everything works great in the sandbox. But do I have issues when I leave there.

A few questions for you

1) - This code is taken from the CesiumViewerStartup.js file. Can i get a quick overview of what is happening here.

require({
    baseUrl : '../../Source',
    paths : {
        CesiumViewer : '../Apps/CesiumViewer',
        domReady : '../ThirdParty/requirejs-2.1.6/domReady'
    }
}, ['CesiumViewer/CesiumViewer'], function() {
});

2) I believe that somehow the code above loads CesiumViewer.js
In the startup function, viewer is defined along with other items.

Using SandCastle and the CZML demo, I have access to viewer because it is defined at the bottom in the require Cesium block.

If I take the viewer app and starting adding buttons and js to the index.html, how can I access viewer and Cesium from a script tag inside the page?

3) Can someone show a simple page that
-is outside of sandcastle
-loads the viewer widget
-has a button in the html page that does something with the Viewer and Cesium
for example:
    function useBuiltInCzml() {

        viewer.dataSources.removeAll();

        var czmlDataSource = new Cesium.CzmlDataSource();
        czmlDataSource.load(builtInCzml, 'Built-in CZML');
        viewer.dataSources.add(czmlDataSource);

        // Zoom in a little closer...
        var extent = new Cesium.Extent(-2.056, 0.587, -2.010, 0.633);
        viewer.scene.getCamera().controller.viewExtent(extent);
    }

Thanks for your help.

Eric

2

I know the answer to question 1 now. Still could use some help on 2 and 3