In what folder should I install my socket.io app? - node.js

Question

I'm on shared hosting and let's say my domain is example.com and I want to run a socket.io app in one folder called myapp so it can be accessed from here: example.com/myapp. Then I install node.js and put the app.js file right under example.com/myapp so whenever I access it I get the confirmation message: hello world node.js. The file looks like this:
const http = require('http')
const hostname = '127.0.0.1';
const port = 3000;
const server = http.createServer((req, res) => {
res.statusCode = 200;
res.setHeader('Content-Type', 'text/plain');
res.end('Hello world node.js \n');
});
server.listen(port, hostname, () => {
console.log(`Server running at http://${hostname}:${port}/`);
});
next, I install the modules, inside the same folder: npm install express and npm install socket.io so I get a folder called node_modules directly under /myapp so the path will look like myapp/node_modules, right?
My question is, where do I put the files of my socket.io app (it's a chat)? The index.js file looks like this:
const app = require('express')();
const http = require('http').Server(app);
const io = require('socket.io')(http);
const port = process.env.PORT || 3000;
app.get('/', (req, res) => {
res.sendFile(__dirname + '/index.html');
});
io.on('connection', (socket) => {
socket.on('chat message', msg => {
io.emit('chat message', msg);
});
});
http.listen(port, () => {
console.log(`Socket.IO server running at http://localhost:${port}/`);
});
Should I put it in the same folder as app.js or somewhere else? Because if I put it along with app.js then this happens: if I access example.com/myapp I get the "hello world" page, which I don't want whereas in order to see the front page of my chat app I need to add a / like this: example.com/myapp/ but that is not accepted by cpanel as a valid application on the application manager. What's the right method to do this?
Thank you.