I need help to ilustrate a Speedometer

Hi hi, I’m trying to make a speedometer from scratch, I don’t have any experience on this and watching a tutorial I managed to make the resource and script.

(Reference link: FiveM Scripting 6 - Creating a Speedometer Using Conditionals and Math (Lua) - YouTube)

The thing is that I would like to make the illustration but I can’t find how to do it?
I downloaded several scripts and when I open the html I only see a blank page.
How do you do to edit the speedometer and make it look good?
Do you run the script and see it in the game, edit it and then restart the script?

HTML and CSS is how you design it
This is what you’re looking for