How to create an NPC using rAthena's scripting:

map_name,x_cord,y_cord,npc_facing_direction -TAB- script -TAB- NPC Name#HiddenName -TAB- Sprite ID,{
   mes "[NPC Name]";
   mes "Hello World";
   close;
}

Common Script Commands:

• mes
  usage: mes "<message>";
  info: displays a line of text in an NPC's dialog window.
• close
  usage: close;
  info: displays a "Close" button in an NPC's dialog window.
• next
  usage: next;
  info: displays a "Next" button in an NPC's dialog window.
• getitem
  usage: getitem <item id>,<amount>;
  info: gives the player an item.
• delitem
  usage: delitem <item id>,<amount>;
  info: deletes an item from the player.

Script Command Documentation:
All the script commands in rAthena can be found here.

How to enable your NPC:

1. Save it as a text file in your /npc/custom/ folder.
2. Open /npc/scripts_custom.conf
3. Add the following line:
   npc: npc/custom/name_of_your_text_file.txt
4. Save and close.