State allows you to change the content on the virtual dom instantly.

A React component is the key part to this whole thing. At the very basic, a React Component looks like this:

import React from 'react'

class Navigation extends React.Component {
    constructor(props) {
        super(props)

        this.state = {
            something: "Text!"
        }
    }

    render() {
        return(
            <div className="navigation">
                {this.state.text}
            </div>
        )
    }
}

export default Navigation

You can use this a good starting point for all of your components.