Step 4: Installing the diodes
Bend the leads of 5 x 1N4148 diodes to come out the the space at the bottom, with the cathode (-), banded side pointing towards the LEDs. The anode (+) end will attach to the micro's pins. If you find the wires too flimsy as a connector, reinforce them with a heavier wire.
Attach the cathode ends by thin wires to the LED's anode (row) ends: pin 12, row 1; pin 11, row 2; pin 10, row 3; pin 09, row 4 & pin 08, row 5.