Material libraries

I am designing a dormer for my camp in 3D and I am trying to generate a realistic rendering.

I have assigned some materials to the roof and walls, but I want shingles and siding.

I have searched and Googled but come up empty. I am hoping that it is something so easy and obvious, and I am just a dunce.

I have IntelliCAD 8.3 Premium Plus which I thought would do the trick.

H E L P Please