@LegendNoobz
If you want to make your own furniture, with your own custom values, you'll need to use the game's built-in tools to create furniture. That does mean you'll need to supply a .fbx file and go through the process of creating a piece of furniture though.

So if what you want to achieve is just modifying the values of existing furniture, this mod will NOT help you. You could, but you'd need to dump the game's models so you could re-use them.

This mod just lightly supplements the process of making custom furniture by allowing you to customize its Capacity/Range, and registering it with the UI for you, so that players can see that your furniture gives X amount of resource or has Y amount of range.

How to use this? Is there a UI in game to edit Custom Range? Or i need to make new furniture.json like on the website you refer to help?