The question is a bit vague:
you say change material att but then change colour / intensity of a light - which one is it? Also, how is it supposed to be random if its based on another value? Perhaps you want to add some random value?
Here’s light colour and intensity:
Above, you could read the location of the actor rather than the value spat out by the timeline instead.
If you wanted to push a value into a material, you’d need to have an exposed parameter, create a Dynamic Material Instance and assign it to a, presumably, mesh.