LOL. funny you should ask! I don't have all the answers but I do have two Substack newsletters and I just recently published a post called, "What is a Newsletter, Anyway?"

I don't normally try to foist links onto someone's comment section, but since you asked, and since I've given a little thought to it, I'll include it here. (You don't have to read it, of course.)

https://writereverlasting.substack.com/p/what-is-a-newsletter-anyway