docs: add plugin setup guide

plugin/lib/commonlibf4/include/RE/B/BGSInstancedQuestObjective.h

@@ -0,0 +1,17 @@
+#pragma once
+
+namespace RE
+{
+	enum class QUEST_OBJECTIVE_STATE;
+	class BGSQuestObjective;
+
+	class BGSInstancedQuestObjective
+	{
+	public:
+		// members
+		BGSQuestObjective*                                 objective;      // 00
+		std::uint32_t                                      instanceID;     // 08
+		REX::TEnumSet<QUEST_OBJECTIVE_STATE, std::int32_t> enstanceState;  // 0C
+	};
+	static_assert(sizeof(BGSInstancedQuestObjective) == 0x10);
+}