OK, with OpenPLi, this should get you going:

Connect the cable from the dish to tuner A on the back

Go to Menu ->setup -> service searching -> tuner config - tuner A
Put in these settings:
Config mode : advanced
Satellite : 160.0E Optus D1 (scroll left / right to get it)
LNB: LNB 1
Priority: Auto
LOF: User defined
LOF/L: 10750
LOF/H: 10750
Threshold: 18000
Voltage mode: polarisation
Increased voltage: no
Tone mode: Off
DiSEqC mode: off
Tone burst: off

Save those settings

Go back a level and config tuner B
Set it to loop through to tuner A

Save again and that should be your LNB settings correct. If you have a channels list of NZ channels, see if you get anything now. If not, start a scan.

Go to Menu ->setup -> service searching -> manual scan
Type of scan: predefined transponder
Satellite: Optus D1
Network scan: yes
Clear before scan: no
Only Free: yes