Odometer scoreboard with Javascript

For my current project, I'd like to have the score displayed within an odometer as it suits the theme of the e-learning. The trainees gain kilometers for every good answer.

I have no knowledge on javascript, but I have found an odometer on github: https://github.hubspot.com/odometer/ . The usage seems quite straightforward "include the javascript", so I've added the code in an "execute javascript" trigger. But here I start to lose my way, I've attached the project file, any guidance/feedback is greatly appreciated;

• How do I add a CSS theme in storyline?
• How do I get the odometer to show in storyline?

I found a useful YouTube video that should be able to guide me in getting the variable %s_score% to the odometer.

If you have any advice where I should start in order to master javascript for storyline that would be greatly appreciated for future projects :)