All materials need to be Material instances of any of the materials available in the Assets>Materials folder:

As a general rule, always choose the most performant type of material:

• m_base: Just a diffuse color texture
• m_base_normal: Same as above but with a normal map
• m_base_cutout: Diffuse color texture with the alpha channel working as mask
• m_base_pbr: Regular PBR material with diffuse, metallic, roughness, and normal maps
• m_base_masked: multilayer material with an RGB mask

How to create a new material

1. Select the base material you want to use.
2. Right click on it and select "Create Material Instance"

1. Move the recently created material to your plugin content folder

1. Double click your newly created material and replace the default textures with your own

Textures

Make sure to reduce the texture size to a maximum of 2048x2048 pixels.