Hi, at 21:10 there is a reference to the textures such as
* Ambient Occlusion
* Albedo Transparency
* Metallic Smoothness
* Normal
1) How do I generate such kind of textures for my own models?
2) Could you please recommend me some courses for generating such textures in a PNG format that can be later imported into Unity?
Ah, yes! These models in particular were textures primarily in Substance Painter as part of an older course: https://cgcookie.mavenseed.com/lessons/prepping-models-for-texturing
A 2.8 version of the same workflow can be seen in the sci-fi door course:
https://cgcookie.mavenseed.com/lessons/exporting-to-substance-painter