Assuming that you have root access on your server.

Initialization steps:

1. Install node.js on your machine
2. Create a new node project and install Express npm install express should do the trick
3. Setup a basic http server and now you must make decisions on how to field the requests
   1. If you plan to run everything over regular http then you can probably just have the node server listen on port 80 of your machine. (Really should run https)
   2. If you want to run https (and thus have a domain name) then I would take the time to setup nginx to listen to port 80 (to redirect to 443) and 443 (TLS port) and then have it serve as a reverse proxy for the express server. Thus the node server could just run on localhost:3000 for example. (If you want a free certificate for SSL you can use let's encrypt with nginx)
   3. My Suggestion: Use nginx as a reverse proxy either way
4. Setup your request endpoint, a post request endpoint for example.
5. There are a few ways to clone a repo through node, using shelljs is one way.

What the express server may look like by now:

const express = require('express');
const shell = require('shelljs')
const app = express();

app.post('/createfile/:data', async function (req, res) {
    if (!req || !req.params || !req.params.data ) {
        return res.status(400).send("Malformed url");
    }
    // I assume the data in the paramas is the url to the git repo
    const giturl = req.params.data;

    // You should probably lightly check the url to make sure its a valid one on the surface level.
    
    const path = 'absolute/path/to/folder'
    
    if (!shell.which('git')) {
        shell.echo('Sorry, this script requires git');
        shell.exit(1);
        return res.status(400).send("Not supported");
    }

    shell.cd(path)
    shell.exec('git clone ' + giturl, function (code, stdout, stderr) {
       console.log('Exit code:', code);
       console.log('Program output:', stdout);
       console.log('Program stderr:', stderr);
       if (code === 0)
           return res.status(200).send("Success");
       else
           return res.status(400).send("Issue with clone")
    });
});

const server = await app.listen(3000);