Nikon D3100 timer length?

I know how to change it into timer mode, but how do I change the time length? I want the timer to be 2 seconds long, not 10. Any help anyone?

Read the manual

it's a great source of everything you need to know and many things that no one needs to know

You need to have a timer remote, try to look for one like the link below around your place, and you can set whatever time you want.

http://www.dslrplaza.com//31-remote-control/167-timer-remote-shutter-cord-n3.html