Thanks for the feedback!
I followed this approach for marching cubes in general: https://paulbourke.net/geometry/polygonise/. You can check out the source code for my game if you wanna see how I did it. (Though it's in a GD extension). And I use a chunking approach similar to Sebastian Lague's though his is in Unity I believe.
If you wanna mess around with it, I'd advise to just follow Paul Bourke's algorithm and implement it in GDScript first. And use the SurfaceTool class to build the mesh from the list of vertices generated by the algorithm.
If you really wanna understand it you can try marching squares as a 2D version to better understand the algorithm behind marching cubes. Which I also have in Godot here and this video by The Coding Train explains it well.
I think you can possible make it super performant using compute shaders, but unfortunately web builds don't support them so I didn't try to in this game.
Hope this helps! And thanks for playing!