Looking for Resources to Create Interactive NPCs and Quests in Minecraft

Hello everyone, I’m new here. I’m currently working on a small fantasy RPG map, but my knowledge of command blocks is still very limited. I found this group while researching datapacks, and I really hope I can find resources here to help me create quests and add more interactions to my Minecraft world.
I’d like to create an NPC that talks to the player when clicked, offers quest hints, and changes dialogue after certain events—like defeating a boss or completing a quest. Something similar to what you see in adventure maps made by mick_05.
I’d be very grateful if anyone could share useful materials, or suggest a clear learning path that I can follow to develop and improve my map. Thank you so much!