I had the same problem when i got this lens with my D7000 as well. What you do is notice the the writing on the lens, and the attachment white mark on ur camera, all you have to do is put the writing on the side of that white mark and twist your lens to the right where the writing on your lens stand on top when the lens is click in, do this a few time you will be good at this. This lens is a bit confusing as it does not have the white mark for attachment on it, and in the manual there is no where telling u how to do it.