Congrats on being invited to the test!
The Hudson a-RAT 3r is your typical inductive reasoning test that seeks to assess your non-verbal intelligence. Google online for tests where you have to guess the next shape in a string of figures.
The verbal part tests your verbal comprehension. You can find many sample tests with this format as well, so practice shouldn't be an issue.
Make sure that you also practice for good time management, instead of only training the skills that you need for the test.