How to adjust the aparture and shutter speed for nikon d3000?

What's the aparture? I don't understand any of it. Can you explain to me. How to to the aparture? What situation? For shutter?

Check around here, there's some good articles on these subjects.
http://en.wikipedia.org/.../Main_Page

Http://www.cambridgeincolour.com/tutorials/camera-exposure.htm

On page 71 of your user manual and you will see how to set the aperture of the lens, use the shutter speed and use the light meter

Read the camera's manual. Twice. Then read this.

http://keerok-photography.blogspot.com/2011/05/what-are-best-settings-for.html

Find a used book store and get some older books on photography from the 70s or 80s

all the basics are covered with reasonably good explanations of aperture, shutter speed, ASA or ISO, DOF etc etc 90% of all that will be directly applicable to modern cameras and you can't beat the price

as others suggest thoroughly read your user manual to translate what has to be done [ as older books suggest ] to how to do it with you camera

Sounds like you need to take a photography class.