I downloaded the version editor.babylonjs.com/BabylonJS Editor.zip which was probably 3.1, I do not really know because it dies after 20 seconds without stack trace. Before, it asks about getting 3.2 which it never does. 3.1 is rather old and more importantly, it does not work. Then, there is an “npm-installed” editor 4.0 no idea how to run it.
Could you suggest the most sensible way of getting a local newbie workchain, with the editor and the www server going at its ends, and some build scripts in the middle. And some overall architecture justification to get the picture. A tutorial “before first steps”. By the way, why the commands from “First steps” warn about missing package.json?