Most cameras are connected by the use of a usb cable. The cable is connected to the back of the computer and the other end to the camera.
The camera is then switched on and should be detected as a removable drive. Check your manual for the correct way to download pictures.
You could of course use a card reader where you remove the card from the camera and insert it into the card reader and download from there.
Camera shops can print photos straight from the card in your camera.