Hi creator, it is nice to see more people making rpgmaker, but I would recommend you check out some tutorials. I learned a lot from this series:
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Things I noticed: when you want to make an event to transfer the player to another map you can use "left-click->quick event creation->trasnfer" this will make that you character is directly transfered to whichever map you want (instead of having to click everytime, you can also set this manually in the event menu by setting the Trigger to "player touch"). To avoid being send back and forth constantly, make sure you transfer your character one tile away from the transfer point in the target map: for example when you transfer from the world map to the "Duengeon 1" map, intead of making the player appear on top of the stairs (where you will set up the event to return to the world map), make it arrive one tile to the right.
I would also suggest you use the inbuilt character creator, for which you can find on the internet many add-ons to add colours (for the green skin), clothes, accesories, etc. At least you could use it for the NPCs, the image of the first goblin you talk to corresponds clearly to a Zombie with green skin, not to a goblin or ork. There is also art available online for this.
Good luck!
EDDIT: also the first crystal re-appears everytime you re-enter the dungeon, you can set an event to permanently dissapear by in the event menu setting "event self switch-> A ->on", then you make a new event page that you leave empy after you set up the condition to "self switch -> A"