I am sure some of them are on youtube. If you cannot find them, try find a video of a Norwegian spelling the letter E (AY) or a word that says Nei, Eller, Enig, Energi to state a few examples. NERGAL is pretty much straight forward for Scandinavian people. The A (this A in the word is a little diffirent though, it isn't a straight forward A I think, sounds more like the letter Æ in the Norwegian alphabet) you can find a video of the words Alene, Allergi, Amerika, Anerkjenne, Ære, to get the idea of the pronunciation.
Personally I vibrate it straight forward and the effects are great.
Try to find some JOS channels on youtube, I do remember that people posted videos of this a while back. Maybe not Nergal, but many.