coding help

I've been trying to edit Evelyn's dialogue, but no matter which way I try it, the changes aren't reflected in-game. The portraits and sprites change as intended, though. It seems that just the dialogue changes are being ignored all together. To test my coding, I downloaded this mod, which does...

Hello! I'm Cristal and I'm a first-time modder. I've been working in my NPC for about a week, and I thought it was ready but when I tried it, it didn't work. This is what's shown. I have rewrited the content.json many times already but it still doesn't work, I don't know what I did wrong... Help :c

So I want to create a mod that gives the NPCs new dialogue (all of them), and I have all the dialogue written down but I just have one problem - I have no idea how to code. Is there anybody who can help me code this mod? I don't really care about getting credit too much but I just want it to be...