make sure your properties box is shown. This can be access via the "tools" menu if it isn't.
Select the viewports you want to turn on.In the properties box there is a section called misc. The top item in this is "on" click in the right hand side pane (where it will say "no") and a down arrow will appear. Click on this down arrow and select "yes" Your mviews will now start to work.
Select the viewports you want to turn on.