Help n00b Insert Header Logo

Hi there WP pundits from all around the world! My request is simple – I need to insert a logo into my header at https://www.maindevice.com; being a n00b in coding, obviously, I don’t understand anything.

I know I have to go into header and replace this

<h1><a href="<?php echo get_option('home'); ?>/">
<?php bloginfo('name'); ?></a></h1>

with this

<img src="<?php bloginfo('template_url'); ?>/images/logo.png">

but I am not quite sure if it will fit and, if it will delete by subline….

please, do help!