Rock4C Enable Gadget Printer (OTG)

I have just obtained a Rock 4C - I have previously used the Banana Pi, Odroid C1 and C2 to create a gadget printer on the USB port.

I have enabled the OTG port as per https://wiki.radxa.com/Rockpi4/dev/usb-host-and-otg-switch-on-rock-pi-4

However, I can’t see how to add the g_printer module as the device is not created on startup. Can someone jog my memory.

Thanks