When you first start using ITDocs, you have no data stored - no Parties, no Products and no Shipments.
Before you enter any shipments, you need to add Parties and Products, at least for the first shipment you plan to create.
Read through the following sections on adding Parties and Products to find out how to do that.
Once you have Parties and Products stored, you can use them to create Shipments.
If you have an urgent shipment and the parties aren't yet added, you can add them while entering the shipment data. Check the section Adding a Party in the International Transport screen.
Adding products must be done through the Add New Product set of screens.