Connecting to your backend is the process of making it possible for your internal systems to communicate with CIC. To connect to on-premise back-end systems, you define Endpoints (which specify transfer protocol and data source) and a Data Flow (which pairs two Endpoints as source and destination of a transfer).
Express provides File-based Integration to connect with your back-end systems. File-based integration allows you to integrate with any backend application that can import files (for example, Purchase Orders or Load Tenders) from a file system and export files (for example, Ship Notices or Invoices) to that same file system for Express to pick up and process. You create a File System Endpoint for the file system where you want Express to exchange files with your backend system and a Data Flow to connect to Express. See File System Endpoint for more details.