When I run houdini it says houdini master. Not apprentice, is this the right version if I am trying to run Apprentice HD?

If you run Apprentice HD then Houdini window title should be “Houdini Master HD Non-Commercial”. The plain Apprentice would have the title “Houdini Master Non-Commercial”.

It means that it is the Houdini Master running on Apprentice (non-commercial) licenses. There is also Houdini Escape that also may run in Apprentcie (non-commercial) mode, though it is quite rare these days.