How to create a PBR from multiple images

Hi there, very useful thread.
I’m not so skilled in texturing so i try to figured out if i understand.
Referring to this thread Open Source Free Textures Library for Babylon and in particular referring to this material Free Mud Dirt Ground Texture Seamless Background PBR - 3Designer, what are the texture i’ve to use for PBRMaterial?
For albedoTexture and bump ok (color and normal GL). For Occlusion and ambient if i understand right i’ve to use the AO in the metallicTexture and then using Occlusion form Red and Roughness from Green. Is it right?
When am i supposed to use the other textures (ORM, spec, Detail)?

Thank’s in advance!