In Dashboard > Appearance > Themes page. There is a list of the theme that you installed.
In case to add the code above (Skype Protocol), you need to activate the child-theme first from that page and after you activate the child theme, then you can add the code above through Dashboard > Appearance > Theme Editor > functions.php.
One more thing, because you are using
live instead of
skype, you need to change this
$protocols  = 'skype'
$protocols  = 'live