How do I s-off my M9 Unlocked Edition?

Unlocked M9 here with Team Venom ViperOne 3.1 ROM and OS-1.32.617.30 listed in download mode.

How do I s-off my phone? To my understanding I can't use Sunshine.

I eventually want to flash M9_2.8.617.4_NoWipe_TWRP_2871b1_rename_to_ROM.zip to it then the ViperOne 3.5 ROM.

Thanks!