Then it takes the order. Every Shop and Buy button opens a checkout page on the site itself: a product gallery with four thumbnails, size chips, a quantity stepper, a live total, and a short form for name, email, phone and shipping address. When someone places an order, the shop gets the order by email, the customer gets a confirmation, and the page hands off to whatever payment link you already use. Stripe, Shopify, Polar, Gumroad, any of them.