Manual Focus On D7000?

Hi guys i just bought Nikon D7000, i'm a begginer photographer, i watched so many tutorials about manual focus… Still i can't understand! What should i do?

Your lens must be in the manual focus mode if that is an option on the lens (not all lenses have AM/M switches). The camera must be in the manual focus mode too.

Look on page 99 of your user manual

Without knowing what exactly you're having trouble with, it won't be possible to assist you here either. One can't do the job of a multi-page tutorial in just a few sentences here.

So… What exactly do you have trouble with? Have you switched camera and lens to manual focus? There's a switch on the lens, and one on the camera near the lens mount.
Are you then turning the focus ring on the lens to focus?

If so, then you're already doing what you want - focusing manually.