Before you order a shop, it helps to clarify your product range: what you sell, roughly how many products, whether there are variants (sizes, colours), prices and promotions. That affects the choice of platform (e.g. PrestaShop, WooCommerce) and scope.
Next: payments (e.g. Stripe, PayU) and shipping (courier, parcel lockers, rates). Integration with accounting or warehouse is often needed — best agreed from the start.
Having content ready helps: category descriptions, terms, returns policy, contact details. Then the launch goes smoother and the shop looks polished from day one.