Google Tag Manager Triggering for Buy with Shop Pay

[ImpTeamMember]

Hi there, 

I am working on a customer's site and they're interested in tracking the amount of users who click on the "Buy with ShopPay" button on specific product pages. When I click through the process in the GTM debugger, I'm not seeing any events firing off which leads me to believe there's nothing being captured here by datalayer. 

Additionally, "Add to Cart" doesn't send a traditional link or element click event, but instead does a "form_start". Can this be modified, or should I set up a trigger using those elements instead?

Can anyone provide any insight on how I might be able to tackle this challenge? 

Thanks!