Textures

[umbral flame]

Hello what is the best way to implement textures from poly haven ? where to place each image ? in the material for the best result ?

[unkempt wren]

That depends on the shader you are using. Different shaders will have space for different (types of) texture maps.
Though generally Diffuse is Albedo in Unity, the rest should largely have the same name (if supported by the shader).

[torn cairn]

format wise, I'd probably take the png version, it's uncompressed while still having a smaller size (or let's say it is compressed but without loss of information)
otherwise, the shader you use usually determines on which texture slots you have to put the textures
shaders for the new pipelines also combine multiple information into a single texture
you might have to look that up for the specific shader you wanna use (like "Lit" shader in URP) and you should see a description of what each texture has to be
if your textures don't match perfectly, there are tools to package channels from different textures into a single one
like this
https://github.com/andydbc/unity-texture-packer

so generally I just recommend to look up information about the builtin shader you want to use and which textures it needs
or make your own shader for it

textures combining AO/rough/metal are common in unreal, but I don't think I have seen a unity shader that takes this information the same way (also since unity made the decision to use smoothness, which is basically "1 - Roughness" for shader output stuff)