To apply a Master page to a document page you should be able to drag the Master page thumbnail on top of the document page thumbnail. Alternatively, you can choose Apply Master to Pages from the Pages panel menu.
To create more than a two-page spread, you need to go to the Page panel menu and uncheck Allow Document Pages to Shuffle. Then you can use the Insert Pages command (or carefully drag thumbnails from the Master page section) to create a three-or-more page spread.
Thank you, that's exactly what I wanted to know.