I’m new too! 
I am following a function input for materials as well off of youtube and it seems to be working rather well. Here’s the link (hope it shows) - it’s by Ratsgame:
It seems like this might be the way to go, even if you’re importing from world machine since you can tweak variables and how things look after import. I also found that sometimes you have to be very careful about how you import or make your map. There are preferred sizes by the engine, sometimes it’s just about lighting, and a host of other variables it seems.