NPCs are essentially a safer method of using /g2animent
In game, simply /amnpcspawn <npcname>
and it runs g2animent based on the file's data

NPC files are stored as npc_NPCNAMEHERE.cfg

To edit NPC filess manually, I recommend notepad++ http://notepad-plus-plus.org/

On each line of the npc file you can specify any datapoint in the form name:value
(Like 'weapon:blaster')
If you specify the same name multiple times, the last one will be the one used
The following names are available:
model, weapon, health, sound, alignment