What should be the contents of the app.js file?

I purchased hosting, installed NodeJS from cPanel

When entering the keepitsimple.bg domain, Hello World is written - set by app.js

I have uploaded all the necessary files to the "keepitsimple/public" directory

Can you make it so that when the domain keepitsimple.bg is opened - the "/keepitsimple/public" directory is opened?

What should be the contents of the app.js file?

app.js:

var http = require("http");

http.createServer(function (request, response) {
   // Send the HTTP header 
   // HTTP Status: 200 : OK
   // Content Type: text/plain
   response.writeHead(200, {'Content-Type': 'text/plain'});
   
   // Send the response body as "Hello World"
   response.end('Hello World\n');
}).listen();

I am attaching 2 images of the directories and the app.js file

Hello,
I used Gulp.js
I installed it, but now when loading the domain it gives me an error, and when loading index.html - the site loads.

https://keepitsimple.bg/
https://keepitsimple.bg/index.html