The source code should be reasonably well commented, but here are some examples to get you on your way. See the <humblr.edvanbenihm.com> for a more extensive version of this doc.
Create an instance of Hublr
$baseHostname = "david.tumblr.com";
$tumblrConsumerKey = "ESeVhsqqFQffufDFsdaZJk3Mks1zM8UiZBWUzGYVwZ8eU";
$humblr = new Humblr($baseHostname, $tumblrConsumerKey);
Get the first 9 posts
$posts = $humblr->getPosts(array('limit' => 9));
which will give you an array of objects with some of the (but not limited to) following attributes
$post->post_url;
$post->photos;
$post->caption;
$post->note_count;
$post->tags;
Get Blog Info
$info = $humblr->getInfo();
echo $info->name;
echo strftime("%V,%G,%Y", $info->updated);
echo $info->description;
Get Blog Avatar
<img src="<?php echo $humbler->getAvatar(128); ?>" width="128", height="128" />