This isn't particularly Essentials-related, so here's a simple enough tutorial on eventing quests in RMXP.
thank you very much for the informationAlready Marin made one it's called Easy Questing Interface ,and now I'm using that resource in my game (base essentials 17.3) it working fine ,I don't know it's working on essentials18.1
Just try it.. link - Easy Questing Interface