You can prep for the test, but instead I would advise you to become as good a Mendix consultant as possible. Why? Because that is what the tests are actually testing. If you are good and know a lot about Mendix, you will pass the test.

To do that:

• Do as much academy trainings of Advanced-level as possible.
• Read the forum-posts and to see what problems people run into.
• Maybe you like the youtbue channel
• Work on Mendix projects, preferably in a team so you learn from others, preferably on more than one app