I am using the free apprentice edition and working my way through the tutorials. In the tutorial videos the Mplay viewer has a row of top menu items:
FILE, VIEW, RENDER, ANIM, IMAGE, WINDOWS
In my version these items are missing. Does anyone know how to bring them up?

Are you running on OSX?

I'm using OSX and running Houdini 10 apprentice. I have now found these menu items, they've been taken off the Mplay window and placed along the top of the screen.

Yes, that's how OSX applications behave.