Scripts for beginners.

kycaka, please refer to the FAQ in the link in my signature:

a neutral monster is present

question "How to perform an action when touching a specific monster?"

displays a text message

question "How to display a simple text message?" (and possibly "I'm trying to display a text message, but it doesn't appear. What should I do?")

the monster disappears

question "How to remove a specific object from the map?"

a specific building appears

see the CreateDwelling() function in the documentation.