Your motors evidently have the drivers built in, so see https://duet3d.com/wiki/Using_external_drivers. For SCARA configuration, see https://duet3d.com/wiki/Configuring_RepRapFirmware_for_a_SCARA_printer and my blog https://miscsolutions.wordpress.com/2017/08/27/converting-the-robotdigg-scara-printer-to-duet-electronics/.