Mega Menu dropdown to Sub Menus..

I’ve installed the Mega Menu plugin and been trying to use it on my new website but when adding it in I can see the Menu Bar with all that has been setup but can get the dropdown see the Sub Menus…
Do I have to get the pro version for this one or should at least just work to see how it is going to work on the website?

Can you please help/advise?
kind Regards

Paulo