Click on the ">>" buttom and click on the item what you want in the NPC,
Protection Merchant=Armors
Weapon merchant= Weapons
Accessory Merchant= Acc's
Liquid Merchant= Pots etc.
Generic Merchant= AP items
lol, with ShStudios you can edit the name and the faction, after make that, you can select the section of Merchants and put the items which you want..
i hope help you