Hi Sharon,
Just add fullscreen-toggle="click" , or fullscreen-toggle="double-click" if you prefer opening fullscreen with a double-click.
You can find examples of both options on the plugin’s Guide page, around Samples 26 and 27.
This applies to the current plugin version. My apologies, but I will most likely release a breaking change in version 2.4.0 soon: lightbox mode, rather than fullscreen, will open by default, and these parameters will change slightly as well. Feel free to post here again if you need a little help after updating.
Best regards,
Jan
P.S. A lovely page you have! A golden retriever is part of our family, so this is close to my heart 🙂