With the LEDs in place, the next step was to get them soldered together. The circuit works with positive legs of each LED joined together, and running off a 5V supply. The ground legs of the LEDs are joined in groups of 4, and these are grounded via a transistor when required.
There are 15 blocks of 4 LEDs on each side of the board. To easily identify them, I named them L1-L15 and R1-R15 for the left and right sides respectively. The pictures below show the wire soldered to the legs of the LEDs:
I then soldered a wire from the ground legs of each group of LEDs, which will be connected to the transistors. By taping it in place, it allowed the wire to hold steady when moved, and therefore keep the soldering intact.
I used cable ties to keep the wires organised, and made sure to label each wire so I could easily distinguish bewtween them later on.