Facebook events feed

Hello,

Facebook offer what looks like a very simple way to add events from my Facebook, but it relies on being able to access and edit the ‘header.php’ file in my theme.

My active theme is Highend Child and the above file is not available.

See https://www.youtube.com/watch?v=tDcJNAUMgvo for Facebook’s ‘how to’ video (less than 2 minutes).

Can you show me how to get my Facebook events into my website?

Kind regards,
Fred.