Yafray in blender queries

First, how do I enable textures to be rendered with Yafray?

Second, On some of my models, I get this weird problem when rendering with yafray, that doesn’t show with the scanline renderer - solid dark areas appear here and there, where they shouldn’t since it’s a smooth area:/

to use textures in yafray thay have to be clouds, wood, marble or image (i think) to ues images they need to be jpg or tga