$feed = new Feed();

$channel = new Channel();
$channel
    ->title('Channel Title')
    ->description('Channel Description')
    ->url('http://blog.example.com')
    ->feedUrl('http://blog.example.com/rss')
    ->language('en-US')
    ->copyright('Copyright 2012, Foo Bar')
    ->pubDate(strtotime('Tue, 21 Aug 2012 19:50:37 +0900'))
    ->lastBuildDate(strtotime('Tue, 21 Aug 2012 19:50:37 +0900'))
    ->ttl(60)
    ->pubsubhubbub('http://example.com/feed.xml', 'http://pubsubhubbub.appspot.com') // This is optional. Specify PubSubHubbub discovery if you want.
    ->appendTo($feed);

// Blog item
$item = new Item();
$item
    ->title('Blog Entry Title')
    ->description('<div>Blog body</div>')
    ->contentEncoded('<div>Blog body</div>')
    ->url('http://blog.example.com/2012/08/21/blog-entry/')
    ->author('John Smith')
    ->pubDate(strtotime('Tue, 21 Aug 2012 19:50:37 +0900'))
    ->guid('http://blog.example.com/2012/08/21/blog-entry/', true)
    ->preferCdata(true) // By this, title and description become CDATA wrapped HTML.
    ->appendTo($channel);

// Podcast item
$item = new Item();
$item
    ->title('Some Podcast Entry')
    ->description('<div>Podcast body</div>')
    ->url('http://podcast.example.com/2012/08/21/podcast-entry/')
    ->enclosure('http://podcast.example.com/2012/08/21/podcast.mp3', 4889, 'audio/mpeg')
    ->appendTo($channel);

echo $feed; // or echo $feed->render();

require_once 'vendor/autoload.php';