In the video the chocolate material has all the values already exposed at SHOP level. If the values are exposed you can change them using just a wrangle. If the parameters are not exposed, so you have to dive inside the VOP material for change them, you need to use a bind and tell houdini to read the value of the geometry attribute you assigned. If there are other ways (and probably there are) I am not aware of them.
Below the hip file with the 3 different methods: exposed parameters, not exposed parameters and using a bind.