It's impossible to tell from your picture exactly how the LEDs are wired.
Start with just one LED connected between one Digit pin and one Segment pin. See if you can get that one LED to turn on and off. Once you do that, try one digit and two segments. See if you can control the two segments separately. Then go to two Digits with two segments each. If you can control all four LEDs separately you should be able to expand up to 8 digits and 8 segments.