Changing Button Class

Hi, Please excuse my ignorance here as I am a newbie at building my own website on Wordpress. I want to integrate a pop up window plug in powered by Popup Domination. With that service you can link a clickable image (like a "Click Here For More Info" button) and it will play a you tube video in the pop up window (as opposed to taking you off your website and onto the You Tube site) The problem is, as the tech dept at Pop Up Domination, has explained, is that in the Simple Catch Pro Theme all "buttons" have "fl-button" class. What this means is every clickable button on the website will pop up that video unless I create a new button class for each clickable button I create on the site. The tech guy at Pop Up Domination said he could not tell me how to create a different button class in the Simple Catch Pro Theme because the "editors" in each Wordpress Theme are different. If anyone out there understands how to change the button class for each button created, any help would be much appreciated. If you do post a suggestion, know that I am really new at this and the more explicit the explanation the better. Thank you.