In the transaction negotiation stage, first of all, the importer will issue the necessary conditions, inquire with the exporter or express his purchase intention through the intermediary, so that the relevant "supplier" or "exporter" will contact him, or the exporter will make a sale directly to the importer; then, the exporter will make an offer to the importer, counteroffer by the importer, and agree to "accept" by letter and telegram from both parties, complete the offer, and then conclude the transaction.