Discord rich presence for Foobar2000

main.js

/* you need discord-rpc and a discord application in your dev page for this to work */
/* uses the Now Playing Simple plugin in foobar */

/* settings.json:
{
	"client_id": "[bot client id]",
	"nowplaying_file": "D:/foobar.nowplaying.txt"
}
*/

const { Client } = require('discord-rpc');
const fs = require('fs');
const settings = require("./settings.json");

const client = new Client({ transport: 'ipc' });
const startTimestamp = new Date();

var current = "";

client.on('ready', function() {
	console.log("ready");

	fs.watch(settings.nowplaying_file, function(eventType, filename) {
		if(eventType == "change") {
			fs.readFile(settings.nowplaying_file, {encoding: "utf-8"}, function(err, data) {
				if(!err) {
					var lines = data.split("\r\n");
					if(current != lines[0] && typeof lines[0] !== "undefined") {
						var end_at = new Date();
						end_at.setSeconds(end_at.getSeconds() + parseInt(lines[4]));

						client.setActivity({
							state: lines[2],
							details: lines[1] + " [" + lines[3] + "]",
							endTimestamp: end_at
						});
						current = lines[0];
					}
				} else {
					console.log(err);
				}
			});
		}
	});
});

client.login(settings.client_id).catch(console.error);

Total noob question, but how exactly do I use this?