How do i change the texture for the floor?

I’m messing around with the 3D FPS creator for the first time, and I downloaded a grass texture that i want to apply across the entire floor of the level. I thought i just had to create a new terrain, apply the texture to that terrain, then add a terrain component to the floor. However once i added the floor component, i was told that there were no available options for terrains. Please help.

Best off asking this question on the 3D FPS creator forum, or contacting the asset creator…