I have been practicing with a variety of 3D map creation tools in the UE4. The link that did help me was this: https://www.youtube.com/watch?v=w2oDxgeBPlI.
The Unreal Engine tutorial has helped me a bit, but I could not for the life of me figure out how to get multiple layers so I can paint on.
This is what I have so far:
Note: The final map is going to look much different, because this is just for practice.
A quick tip before you try making complex shapes. They are both Geometry tools or BSP.
Game Growth 