Never used that software personally, but it looks like a niche game engine to build a specific type of web game. Learning how to make web games will teach you javascript, but it's gonna be very advanced. I would start with just adding interactive bits to regular websites first such as client-side form validation, making a site theme selector, a hambuger menu to collapse the site navigation into on mobile screens, etc

I see. Thank you for the comment and also for following me

Look up "viewport units" on MDN. Example: body { height: 100vh; }