When you plug it in via the USB cable to your PC, you should see a USB symbol in the notification bar. Pull down the notification bar and click USB Connected. At that point it should give you the option to mount as storage. Your phone should show up as a removable drive on your PC.
If you do not want folders to be scanned for media so they won't show thumbnails, you simply create an empty file and call it .nomedia and place it in that folder you want to keep from displaying.