Adding logo to WordPress header

It says right there in the code:

<?php // to use a image just replace the bloginfo('name') with your img src and remove the surrounding <p> ?>

So just replace this line below that comment:

<p id="logo" class="h1" itemscope itemtype="http://schema.org/Organization"><a href="https://wordpress.stackexchange.com/questions/227227/<?php echo home_url(); ?>" rel="nofollow"><?php bloginfo(''); ?></a></p>

with this:

<p id="logo" class="h1" itemscope itemtype="http://schema.org/Organization"><a href="https://wordpress.stackexchange.com/questions/227227/<?php echo home_url(); ?>" rel="nofollow"><img src="http://example.com/your/logo/url.jpg" title="Your logo" alt="Your logo"></a></p>