To preview a document contained within the library navigate to the “Document  Management” through the “Asset Library” link on the Header Bar.

You will be presented with the following screen:

 

Select the document that you would like to preview by clicking on the item using the left hand mouse button. The right hand frame of the browser will be populated with a “File Details” property page containing the details of the document selected:

 

 

You will notice that to the right hand side of the Title there is a preview icon .   By clicking on this icon you can preview the document that is currently stored in the repository.