Current questions and answers regarding the map editor.

Hello! Could you please tell me how to create my own landscape and make it appear in the editor among the existing landscapes? Do I need to edit the standard game files for this?

Good evening. I used the guides from Hottabych and Esto100nec, and I added tile copies. I don't know how it works with custom textures, but I don't think it's particularly difficult; everything is described very clearly in the guide.
P.S.
Guides from Hottabych's group
The link seems to be broken, so I'm attaching a link to the topic with the guides (find the one you need by its title).