For the health bar I've added some code in index.html for the DOM with elements like <input> .
Some CSS in main.css to style it.
I've added a css class and a css ID in the html of the bar.
Then I've added some variable in storage for the health value of the input to be changed in script.
In script.js at the beginning where you must put functions, I've added a function to show or hide the bar in the script, and another function to increase or decrease the value of the input. Your function selects a specific element (css ID) and then you can change its display from none to flex.
In script then I call the function where I need it to update the value of the health bar in storage.
You don't need the function to hide or show, but I find it useful sometime.
If your CSS/JS change the UX/UI of the health bar according to its value, then you got your health bar.
For the map I've done it myself with some help, but it's very difficult to explain it. Basically you need to code your own modal component but creating a component needs more documentation.
Happy coding and scripting.