look for favicon element then click edit,
upload your image, then you can check it through your url, for example: http://yoururl.blogspot.com/favicon.ico. After that, you need to add code between<head>
<link href='http://yoururl.blogspot.com/favicon.ico' rel='icon' type='image/x-icon'/> <link href='http://yoururl.blogspot.com/favicon.ico' type='image/x-icon'/>
</head>
That's it, you are done. Congratulation!
