how i turn on my camera on my computer

Plug it on your computer/laptop probably via USB. Try to search for any camera app installed on your computer and just run it. If no camera app isntalled yet, try to visit your laptops brand website (if that's a laptop) and look for any camera software that you can download and install for your laptop model. Or try to download and install this software http://www.cyberlink.com/downloads/trials/youcam/download_en_US.html .