So I've dropped a bunch of narration into a .nki file that I'd like to use as a custom instrument in Sibelius. I don't quite understand how to link the instrument when running Sibelius though. I've tried adding a separate instance of Kontakt in the playback configuration, and creating a manual sound set... but Sibelius can't seem to find my file. Or maybe I just can't seem to find it through the various menu options. Any help on how to link custom Kontakt instruments or samples back into Sibelius for playback purposes?

Kontakt 5.7.3
Sibelius 8.0.1
Windows 10
Writescore template 7.0

Thanks!