SSR pin 3(+) > Duet pin 3 (3.3v)

SSR pin 4(-) > Duet PS_ON

SSR pin 1 > neutral in from power plug + yellow wire from power button

SSR pin 2 > neutral to board + green wire from power button

In order for PS_ON to work you have to have M80 in config.g and hold the power button down for 1-2 seconds. When M80 is ran, PS_ON becomes grounded. This is what powers the SSR