How to make a simple UI change in Llama-Server?

[simusid]

I am not a front end developer but I want to make a trivial change to the top of the main page with a MOTD message to my users. Between the old and new UI, regular index.html, typescript, and index.html.gz, I'm genuinely confused as to where this needs to go and how to build it. In short, where would I put

Here's an important message!