How to change the flash settings on the Nikon D3000 to be able to use an external flash?

How do I change the flash settings on the Nikon D3000 to be able to use an external flash?

Take the dang cmaera out of full auto - use full manual @ 1/60-1/250 sec and adjust you aperture accordingly.f/5.6 or 8 should be fine for most situations.

Nikon entry level cameras, including the D3000 do not have the ability to use the Nikon Creative Lighting System (CLS) to remotely control an external flash.

You can use a flash on the hot shoe, or use a cable, such as an SC-28 to remote a flash. Or if you have the correct Nikon speedlight (SB600 or above) you can buy a SU-800 that sets on the hot shoe of your camera and IR wirelessly control the flash.

Finally, you can buy a slave flash of any brand and control it in Manual mode on your camera; either with the camera's built-in flash, or radio triggers, such as Pocket Wizards or Yongnuo RF-603s.