How can I add a token marker to a token?

I'm just getting into using the API. I'm using the GroupCheck skript and this skript by the same guy to apply damage. I have two issues with the apply damage skript. It puts tokens health on negative values and I want it to add the "dead" token marker if the hp goes on 0. The former of those I already fixed by changing "boundedBar = false" into "boundedBar = true" in line 8. The second one is harder. I can't find where it would do that, but I saw it do it in a guy's youtube vido. But maybe he added it himself, idk. I want to add a check in line 92 whether or not newValue is 0. If it is I want to add the "dead" token marker to the token. Adding the check is simple, but how can I add a token marker to a token?

I think Nick had healthauras on during the video.  Anytime a creature goes to 0 or negative it auto kills the npc.  I don't use that api, auras cause lag when everything and their mother have them on.