Firt you need to enable the plugin from the Config menu then Config Plugins. You will then need to restart Mach, after you have done that you will see the diagnostics page for the PoKeys from the Operator menu.
To set up a function you just do as you would normally with the parallel port except for the Port number you use 10, the pin number is whichever one you are using on the PoKeys.
To set up the PoKeys you need to asign the different pins you are wanting to use in the software that comes with the PoKeys, for example if you want to use Pin 18 of the PoKeys for an input then you asign it in the PoKeys software and then send to device to save it. You can then set up that input in Mach.
Hood