Website links ID/Class not working

[alexduncan]

Please can someone take a look at my site, I have a grid of images see photo, which when clicked open a popup.
I need the popups pages to show different content but I can't workout how too do this. I can only display one video.


The person who built the template has put a note in the code.
<!--THIS IS IMPORTANT! to close the modal, the class name has to match the name given on the ID -->

I'm a bit of a newbie to ID and class.

Thanks Alex