• Unpack OldWorldBlues - Main.bsa. filtering with "StealthSuitVoice" makes easier to find voice files.
• convert ogg files to .wav format. need to be 16bit, 44.1KHz. I recommend to use Yakitori Audio Converter.
• Go to sound/fx/VSS/ directory, you should see eight folders. open em and replace every empty wav data with converted files.
• done.
  

If you don't have VSS folder, you need to make exactly same name folders.
process 1-2 are exactly same as Stealth Suit Voice Add-On. Way better article for these is here.
Porting the original Stealth Suit voice files from New Vegas for use with this mod at Fallout 4 Nexus - Mods and community

I recommend you make backup files with this structure strongly. Vortex or MO2 might be overwrite your installed data with empty wav files when you deploy or update mods.
I might be change file structure for ease to install voice files in future.