How many dependencies does manufacturing a light switch have?

I've been trying to understand how various common objects, say, a light switch or a suitcase, are manufactured if we thought about the entire process starting from raw materials. Where do all necessary materials come from for the final assembly? How are those materials manufactured? If we follow down the line, how many dependencies does manufacturing a light switch have and what are they? I recently realized that all these steps are very much invisible to consumers and I'd love to learn more. Any recommendations where to look?