Go to export, select export location and select Create Subfolder.
Click on Advanced Textures Setup
Delete All and click on Add Map
Just make name and textures setup as image
And rename this preset
Chek texture maps, select texture resolution and export textures
Move folder to texture path
Go to asset browser > Assets > Textures > roads (this my path, you indicate your) Right click > Import
Select path to save .DDS textures
Go to asset browser > Assets > Material > roads (this my path, you indicate your) Right click > New Asset > Material
Adding textures
Diffuse > .DIFF
Normal > .DDNA
Specular > .SPEC
Detail > .DETAIL
Heightmap > .DISPL
End, next indicate your parameter this
Shader, Surface Type, Diffuse color, Specular color, Smoothness and more other parameter