How to colorise unstructured grid by values (discrete or continious)

Hi , i’m new to VTK. Result of creating and plotting UnstructeredGrid is left image


How can i obtain result close to right image? Do i have to render or to colorise Grid, how to add color legend? Reading docs without examples didn’t help much

This example may help, it shows you how to add a legend ReadLegacyUnstructuredGrid. This is old but may help: