How to create materials that change according to a stopwatch

I think I’m going to do more without code because I’ve been trying all day with code but I can’t do it even with the documentation and Chat GPT. Could you tell me how to create a material that reacts to a signal from a stopwatch, either by assembling blocks or a Verse script, but then tell me exactly how to build this script.
Thank you very much for taking the time to explain!