In a nutshell, you run:
To setup the initial Apache/MySQL/PHP server.
sudo tasksel install lamp-server
Then setup your firewall as appropriate (allow port 80), and then setup the ownership on the webserver files directory.
Note: use only for non-production web servers - this is not the most secure way to do things.
sudo chown -R $USER:admin /var/www
Then update the index.html and other files in /var/www as fits your website design/intention, then open up a web browser and type in:
To view it from your own computer, or use the IP address of your computer on the network to view it from another computer on you network.
If you do not wish for people/computers to connect to your webserver from outside of your network, you do not need to port forward on your router.