How to adjust Aperture?

I have a Nikon D 3000 and I would like to figure out how to adjust my Aperture. I can change my shutter speed but I can't find where/what I'm supposed to use to change it. I'm on manual setting.

I used to look in the user manuals of different brand and model cameras and find the page numbers to help them figure out the the answer to their questions.

You can do that yourself.

Shooting in the shutter speed priority mode allows you to adjust your aperture, but you will have to look up the answer to your question using the index of the user manual

Press and hold the (+/-) button while you turn the command dial.