I assume you have the Serverfiles downloaded so go to them and open up the matchserver folder. Then open npcset.xml
Code:
<!--
Mansion
-->
<!-- Mansion QL 0 -->
<NPCSET id="10101" name="G01" basenpc="11"> <!-- Random 1 -->
<!-- <ADDNPC npc_id="111" min_rate="15" max_rate="15" /> Goblin Soldier (event) -->
</NPCSET>
<NPCSET id="10102" name="G02" basenpc="11"> <!-- Random 2 -->
<!-- <ADDNPC npc_id="111" min_rate="15" max_rate="15" /> Goblin Soldier (event) -->
<ADDNPC npc_id="12" min_rate="15" max_rate="15" /> <!-- Goblin Gunner -->
</NPCSET>
<NPCSET id="10103" name="G03" basenpc="11"> <!-- Random 3 -->
<!-- <ADDNPC npc_id="111" min_rate="15" max_rate="15" /> Goblin Soldier (event) -->
<ADDNPC npc_id="12" min_rate="30" max_rate="30" /> <!-- Goblin Gunner -->
</NPCSET>
Kind of complicated for a spawn script, but oh well.. (Don't just copy and paste because this isn't an edited code.)