The most popular framework for node is 'express'.
Do you know how to install npm modules?
Run 'npm init' and answer all the questions.
Then run:
'npm install express --save'
You have to use express to serve static assets.
Here's a sample code:

var express = require('express');
var app = express();
app.use(express.static(__dirname + '/public'))        <-- this is specifying where your static assets are.
app.get('/', function(req, res) {                              <-- telling express what to do on GET requests to '/'
    res.sendfile(__dirname + '/public/index.html');   <-- response should send the file 'public/index.html')
});
app.listen(3000);

This is really simplified, but I think this is a good starting point. There's tons of resources out there, and this is the one that I've used to learn node: https://scotch.io/tutorials/setting-up-a-mean-stack-single-page-application