Generate the CSV file with the explained file structure (see step 2) from your internal system (see step 1). Take into account the routing data (see step 3) and any additional required data (link to Supply eInvoicing Integration Guide for Suppliers V1.1 plus link to Excel Sheet with all field names).

Test uploading CSV files (see chapter Transmitting CSV invoices) with just a few invoices and check the invoice data in the user interface.