Node Geometry Editor "Set Material Id" node ID Value

With the new Node Geometry Editor, What ID do I use for the “Set Material Id” node? I want to load a texture into a standard material.

The id is the number of the sub material (as in Multimaterial sense of it). so if you use 0 and 1 then your mesh will be split into 2 submeshes that can then use a multimaterial with 2 child materials:
MultiMaterial | Babylon.js Documentation (