Current questions and answers regarding the map editor.

Hello everyone. Yesterday, I started creating a map with beautiful landscapes and effects, but I encountered a problem: I need to add a new decoration with its own texture to the map. Question: how can I do this? (There are very few interesting decorations in the game, but it seems that they can be added.)
And here's another question: how can I create my own battlefield? (For example, a dungeon or a human city?)
Thank you in advance.