The PSU has three Terminal outputs for 5V. One is used for connecting directly to the Raspberry PI. The other two are each connected to a 6 position screw terminal adapter (https://www.amazon.de/gp/product/B076CGXKBY/) with a 14 gauge silicone cable (probably too big for use case). A pair of ground and voltage terminals can supply an 8x8 matrix directly. The data wires are then connected like shown in a previous log (https://hackaday.io/project/169093-club-matrix/log/172245-from-10-x-8x8-leds-to-40-x-16-leds).