ManjariNair in terms of basic material editing, it can be straightforward, just search on YouTube for how to add materials to an object in blender. For more advanced material crafting and shading, that will require some commitment.
Since the model is already done, it can be as simple as selecting a specific piece and just using a colour sliders to alter the material. It really depends how much effort you want to put in.
This just allows those with little experience to produce a good result with a smaller learning curve.