How to draw subset plot in paraview

hello everyone, I am new to paraview. I want to use paraview to draw the subset plot.
My data is organized in pvtu format, the parallel unstructured grid vtk data format.
I want to draw each set using one color. This is usually used to demonstrate domain decomposition.
I do not know how to implement that. Thanks for your time.

ExtractBlock ?

color by vtkBlockColors