Power connection
You need to extend the wires of the power connector by about 20cm.
To do so take some stranded wire with different colors, strip and solder
to the power connector wires. Use shrinking tube to cover the joints.
Then solder the wires to the power supply board.
The yellow wire gets soldered to the blue wires (-15V), the black wire to
the black wires (GND) and the red wire to the red wires (+15V).