Materials
Depending on how the Fluent Catalyst Asset is built (a default one or created by other creators), the material will have to be set in a different way.
Fluent Catalyst way
if you happen to have a material menu in the Fluent Catalyst menu, use it.
You will then have the ability to Move Your Mouse left and right to scroll through the material list of your scene.
Material Adjustment
You can Hold SHIFT and press one of the numer showing on the list on the left then press Enter to directly assign the material.
Default Blender way
Only if you don't have the material setting in the Fluent menu, you can set it like any Blender object.
Material assign
If there are no settings in the Fluent menu and setting the material on the object is not working, please contact the Creator of the asset