MapSetting
This page will go through the process of setting up the overarching MapSetting components and MapTerrain (not to be confused with uncapitalized "map terrain.")
Important
You can do this!
Before we can start actually creating your Map model, we need to set things up for it. Luckily, this is fairly simple.
Create a new Unity project separate from your dump project, if you don't have one already. It may be a bit awkward to tab between two Unity projects back and forth, but by doing this you avoid a whole host of problems that could potentially arise. It also allows your map creation workspace to be significantly cleaner and only requiring you to bring over what you need from the dump project.
Navigate to Assets/Share/ within your project at the bottom and add a further /Scenes/Map/ directory.
Create a new scene, or rename the SampleScene (cleared of any prior elements that may have been there before) to a name matching the map convention. This will be our map scene. This guide uses S071, though just about anything not used by the game already will work. In order to do this, you need to actually save the SampleScene to begin with, so go ahead and do that even though it's empty. Then drag it into the new folder you made, and rename it to match.
Now that we've done that, we can begin actually working in the scene. Right click anywhere in the SceneView on the left and create an Empty. We're going to call this MapSetting, and it's what the map and the props on top of it will be held under.
From here, it's a good idea to start referring back to your dumped map to emulate how the developers set up the MapSetting Empty themselves. Most scripts should already be included from the Unity template setup, but if you don't have a script included already, you're going to have to copy it over from your dump into your project.
In order to add a script component to the MapSetting empty, use the component view on the right. Click on the Component box and search for matching scripts based on your dump. You should probably get comfortable doing this, you'll be doing it a fair bit.
Add every script to match with the dump map (memo is not necessary but it is harmless if you do) and fill in their values to match. You will likely have to move additional files over, like the MapTerrain, which is the data that handles the tile layout like what's ground, what's a fort tile, what's a forest tile, etc.
Note
Remember that if you click on item inside of the box, it will show where it is in your dump project. From there you can right click on it, open its location in file explorer, and move it over to your creation project.
Make sure to match any folder directories, creating them as necessary to maintain a match with the dump files. For example, a MapTerrain section might need a /GameData/Terrains/ directory created inside of the Assets/Share/Addressables/ directory.
Once you've done that, you're good to go! Move to MapSetting Terrain.