PHP has had a built-in web sever since version 5.4.

PHP's web server provides a router script for use with server rewrites. Magento, like many other applications and frameworks, requires server rewrites. The router script either:

The web server executes the requested PHP script using a server-side include
Returns false, which means the web server returns the file using file system lookup

Example: requests to /static/frontend/Magento/blank/en_US/mage/calendar.css should deliver the file if it exists, or execute /static.php if not.

Without a router script, that is not possible via the php built-in server.

How to install Magento

Magento's web-based Setup Wizard runs from the setup subdirectory, which PHP's built-in web server cannot route. Therefore, you must install Magento using the command line. An example follows:

php bin/magento setup:install --base-url=http://127.0.0.1:8082 
--db-host=localhost --db-name=magento --db-user=magento --db-password=magento
--admin-firstname=Magento --admin-lastname=User [email protected]
--admin-user=admin --admin-password=admin123 --language=en_US
--currency=USD --timezone=America/Chicago --use-rewrites=1

Notes:

By default, Magento creates a random Admin URI for you. Make sure to write this value down because it's how you access the Magento Admin later. For example : http://127.0.0.1:8082/index.php/admin_1vpn01.

For more informations about the installation process using the CLI, you can consult the dedicated documentation that can found in the developer documentation.

How to run Magento

Example usage: php -S 127.0.0.1:8082 -t ./pub/ ../phpserver/router.php

What exactly the script does

The $debug option provides low-level logging for debugging purposes.

Forwarding rules:

Any request for favicon.ico or for any path that starts with index.php, get.php, static.php are processed normally.
Requests for the path pub/errors/default are rewritten as errors/default. This is provided for compatibility with older versions.
Files under request paths media, opt, or static are tested; if the file exists, the file is served. If the file does not exist, static files are forwarded to static.php and media files are forwarded to get.php ((How about opt?))
If no rules are matched, return a 404 (Not Found).

Then rewrite paths for pub/errors/default/ by removing the pub/ part. (was at least needed for older versions)

Request starting with media/, opt/, static/ test if the file exists. If Yes, then handle it, if not "forward" static to static.php and media to get.php

If none of the rules matched, return 404. You may instead include the index.php, if 404 should be handled by Magento or you want urls without index.php/.

How to access to the admin dashboard

When the installation is finished, you can access Magento as follows:

Storefront: <your Magento base URL>
Magento Admin: <your Magento base URL>/<admin URI>