Upgrade Wix Harmony E-Commerce

I created a one-page website on Wix Harmony, not wix classic. I need to add a button (register and pay) that includes consent checkboxes with links to attached policies, contact information and pay. I think there is a wix form that contains all of that. Once clicked, the person will receive automatic registration number and I receive the contact form with their registration number and the payment. The freelancers who contacted me so far are experts in wix classic but not familiar where things are in wix harmony. So please only contact me if you are expert in wix harmony and done current websites on wix harmony, not wix classica. I need to do it, not you. so I need you to give me instructions and guide me so I can do it.