Hi AME Network,
Thank you for getting back to me. Yes, I know what a light box is and I use them myself in many applications.
The part of your question that is unclear to me is what you want to appear in this light box. You mention that it is your “affiliate payment window” but this does not make sense to me in the context of Simple Affiliate Shop. The payment window is normally associated with the Merchant (ie the provider of the affiliate product). Simple Affiliate Shop is for marketers who send visitors to the merchant.
Forgive me if this is all old news to you but you may want to refer to https://www.peoplesgeek.com/what-is-affiliate-marketing/ (are you the affiliate marketer or the merchant?)
You will see from the article that Simple Affiliate Shop does not contain a payment window so that leads me to being unsure of what you want to appear inside the light box. If it is the payment window of the merchant then you could do that by adding the merchant payment URL but you would need to be careful that it includes your affiliate codes since this is the mechanism that allows them to pay you a commission.
Hopefully, that has cleared up what I want to understand from your question – I am happy to help but it is best if I am clear what you are wanting to achieve or I may have both of us going down the wrong track.
Many thanks,
Brian (PeoplesGeek)