having trouble creating 2 custom field options for front page

Hi,

I’m using the custom fields plugin and want to create a way for a user to add either a video or image for a featured item gallery.

I’ve created the fields withing the gallery script, and can get either the video or image field to appear, but can’t figure out a way to show either of them depending on what field has been entered.

The website is https://nouvellelondon.com/isys

Below is a link to the pastebin of the gallery php code.

https://pastebin.com/5iSd30Zm

Thanks in advance!