Where do I find it? I bought a camera board and it says I need to use the UART interface however I can not find it anywhere. Do I download it? do I already have it? thanks for the help
Which camera board did you get? A link to that hardware might help.
Normally, UART refers to a RS-232 interface. If that is the case with that camera, then you would need to get an external device to convert the Arduino TTL serial to RS-232 serial. But that type interface is not very fast. A usb interface is much faster.
Many or most digital cameras (prior to USB) came with a cable that was or contained an RS-232 to TTL converter so that the camera only saw approximately TTL signals just as the Arduino does.
This may or may not be the case here - you clearly need proper information on the camera.