Single Page Checkout in Webflow - Checkout Step form in webflow

Hello there,
I need some help in making a single page checkout in webflow through the steps form. as you can see in the Reference site. When we add an amount of 50 or more the buying option is enabled. and then it opens the form of a step for information and payment. The readonly link is what my client has. The reference site is viviembellish. Gift Cards

Here is my site Read-Only: [LINK]1
([how to share your site Read-Only link]2)