How to set a 30 second exposure on a Nikon n 80?

I understand how to do a longer exposure then 30 seconds but I can't figure out how to do a 20 second or 30 Second exposure. The manual is not much help in this. Please don't be brief.

Set the camera on a tripod, the exposure mode to manual exposure, set the shutter speed to bulb mode, attach a remote shutter release, and using a stop watch or by watching the second hand on your wrist watch, depress the remote shutter release for 30sec.

Of course, you will need a method of metering the exposure and set the aperture accordingly. If out of range of your aperture, then you will have to change to film having a different ISO, use a and filter, or any suitable combination thereof.

Set the mode to 'manual exposure' and wind the wheel until you get the length you want. To get 30 seconds, you may have to wind all the way to 'bulb'

The manual does not help?

If the camera has a 30 second shutter setting, simply set it there. If that SLR has a digital display, it should read 30". If the camera does not have a 30s shutter speed setting, set to Bulb then use your own watch/clock to countdown.