Next.js Full-Stack app (Login + product cart builder, NO PAYMENT INTEGRATION)

I'm a software developer, and I've built out most of a full-stack application. I need help finishing off the rest of the functionalities. The core functionalities: - Product catalogues from 2-3 different vendors - Ability to build a cart, and send an email with the cart details to the user and to us (the admin) - Ability to add, edit and de-list items from the platform