How to turn off built-in flash in D5000 while using remote speedlight flash?

I'm trying to get more light effects using the speedlight. But the light from built in flash also fals on the object. How to turn off the built-in flash in D5000 but also to use Speedlight?
Speedlight: Nissin Di 622 MarkII
Camera: Nikon D5000

Added (1). Hi. Thanks for the response.
I'm using the camera in Manual mode.
the remote Flash with Slave Digital option in the flash, and in Camera I enabled the "e1Flash Control for Built in flash - TTL" I'm a beginner so not sure. What actual information you are looking for. Please let me know if you need more info for my question.
I believe the Camera flash controls the Remote Flash.

Added (2). Got somemore info-- its using CLS
#Jim - I already looked in the manual. It didn't helped my question.

If you'll read your owner's manual it will tell you what to do.

We really need a little more information here! Such as how are you controlling the remote flash. Without that additional information then I could waffle on for a couple of pages and still miss the most simple of things.

*Jim I "sort of" disagree; using a third party, remote flashgun/creative lighting, things come into play that may not be tackled by the standard manual.

I'll make a wild guess as you aren't giving enough information.
Don't use Auto mode. Use Program, Aperture, Shutter, or Manual modes (also collectively known as PASM modes). The built-in flash won't pop up unless you want to use it.

Relevant side note, program mode is the same as auto mode except in program mode the flash doesn't pop up unless you choose to and you can use exposure compensation.