Adding panels

It's very ugly right now, I know. But bear with me.

Trying to understand how JPanels and JFrame's work in java. So right now I have just made it very ugly inside the Program constructor. But just want to get it to work. And I do actually like that I can use HTML inside the elements. Then I think I can style them pretty easily.

Think I'm going to make a new class for the side, like SideList. They can be a panel with with their own private list. Should I also then have another class for reading files?
How am I going to handle when the game ends? If I update the file that's being read from the SideList midgame, do I need to somehow call a function to make it render again with the updated list?