Quixel Suite is a collection of the nDo, dDo, and 3Do photoshop plugins. nDo is a normal map creation toolkit. You can use photoshop's native tools to create normals in real time as well as extract normal, cavity, and ambient occlusion maps from photos and textures. dDo is a powerful texture generator that can make PBR (albedo, roughness, metalness) and legacy shader (diffuse, specular, glossiness) textures quickly from unwrapped 3d meshes set up with color masks. Quixel Suite 2 added the functionality to custom paint on your meshes in 3d across all textures (albedo, normal, metalness, ect) by editing masks. 3Do is a real-time renderer plugin that mimics next gen game engine's HDRI lighting and allows you to preview your texture on it's mesh without ever leaving photoshop.
A description of useful hotkeys are located here:
https://sites.google.com/site/stevengladin3d/quixel-suite
To preview a custom imported mesh properly in 3Do it is recommended you use these settings:.
nDo & dDo overview
Complete dDo character workflow
In depth look at dDo painter
nDo overview
nDo lowpoly workflow demonstration
Complete nDo gun asset workflow
Note: This is an older version of Quixel Suite, however, the concepts still apply.
3Do rendering overview
Additional Learning
Quixel has a very comprehensive learning section with many useful tutorials as well as written software overview documentation available online on their website.