Set the document up as a facing pages. Create a master page for the Left side and a Master Page for the right side which include any headers or footers needed, and type command-3 in a text box for automatic numbering. Then in the layout dialog box, drag the left master page over the left pages and right master page over the right side.
Under the Page menu, pull down to Section. Click on Section Start, and enter the format you want to use and the number to begin with.
B