Taking templates from static-site generators

I'm building a website for myself mostly for fun. The things I want the website to do could almost be accomplished with a static site generator, but I do need a database for a few things.

That being said, I do not want to fuss with styling/templates too much. What should I learn to rip the template & styling from a SSG I like and apply that to my own templates?

I'm looking at docusaurus now, and trying to figure out how its index.html is rendered. The template has the division tags, and I understand that javascript is used to flesh it out.

For example, in index.js :

const React = require('react');
const CompLibrary = require('../../core/CompLibrary.js');
[...]
class HomeSplash extends React.Component {
  render() {
    const {siteConfig, language = ''} = this.props;
    const {baseUrl, docsUrl} = siteConfig;
    const docsPart = `${docsUrl ? `${docsUrl}/` : ''}`;
    const langPart = `${language ? `${language}/` : ''}`;
    const docUrl = doc => `${baseUrl}${docsPart}${langPart}${doc}`;

    const SplashContainer = props => (
      <div className="homeContainer">
        <div className="homeSplashFade">
          <div className="wrapper homeWrapper">{props.children}</div>
        </div>
      </div>
    );

What is props? Do I start by looking at '../../core/CompLibrary.js'? Start by reading about react? About how the DOM is rendered/modified?

Thanks for your help! Any reading recommendations or keywords are appreciated