Chohole - the ReadMe file tells you where to look for the leaf materials.  What I did was to create a cube, then click on M for material, then when I was in the Materials lab I clicked that little arrow (as in previous post) and chose an folder that didn't have much in it, and clicked on Import.  Then navigated to Bryce 5 folder, then Content folder, then (I think) Estevez Real Leaves folder, and added the material.