* solder the PAL IC socket and the pin headers to backside of the PCB. The pin headers will later be pushed into the PAL socket on the motherboard. make sure they have quite the right length as if they are too long, there might not be enough headroom above the PCB for the keyboard and if they are too short, the connection might suffer.
* connect chipA8 to one of the A8 pins of the new RAM chips and CASADR, D3 and D4 to appropriate connection points on the motherboard. The diagrams show some options. If you have mainboard with soldering points for the two different gate array versions, it's the most easiest way to use the soldering points there. Otherwise connections to IC pins are probably the easiest way.
* Finally remove the PAL chip from the socket on the motherboard and insert it into the socket on the backside of the add-on PCB. Make sure you align its direction correctly . (Printed on PCB, Pin must face towards the pins of the IC next to it)