This tutorial shows how to create 3D terrain from heightmap + texture with Photoshop and ATLAS plugin. For this tutorial we used high-res heightmaps and textures from https://www.3d-mapper.com. You can download your own set from a location of your choice.
Resources
Heightmaps+Textures: https://www.3d-mapper.com
ATLAS plugin: https://www.3d-map-generator.com