applying textures in cycles render

so i need to apply a texture to my rocks but when i go to texture tab it comes up with this

someone help me please also tell me what you think of my landscape its my first real attempt using blender, thanks.

Right now you are looking at Cycles World Texture settings. You want Object Material settings be visible. Click on the brownish cube icon in the right upper screen part, then Material sphere icon next to it . It is handy to keep Node editor window open while working with cycles materials and textures:

A bit naked scenery, but overall nice image. You have done good job.
Happy blending!