Open the notification bar and there's an icon with two circular arrows and either a rectangle or lock between the settings icon and date. If its a lock then your orientation is locked in Portrait... tap it and it should turn into a tilted rectangle which will allow the screen to go into landscape. The home screen won't rotate though without some work
but most everything else should.
Mine was locked in Portrait when I got it which threw me too
Let me know if this doesn't work.