So I've checked out pretty much all the modding guides on here and other sites but some of them are out of date and other I just didn't understand. I'm a writer, have very limited coding knowledge, and I want to write extra dialogue and events as a mod but I have absolutely no idea what I'm doing. I need someone to explain to me "for dummies" style what to do.
I suggest that you join the modding channel of the Stardew Valley discord. There are a number of folks making dialog mods and new npcs who have lots of experience to help you out. Other than that you're going to need Content Patcher to load your stuff into the game. You can also look at some of the dialog mods on Nexus to see how they do it.
When you get on the Modding channel.. look me up. I am well versed with Eventing and Dialogue as well with NPC functions