You will always need to create a Key Pair. The key pair contains both your public and private keys. To share your public key, select the key pair from OpenPGP studio and click the Export Public Key button. Save the file and then share it with your trading partner. When your trading partner sends you an encrypted file using your public key, you will decrypt the file using the private key stored in your key pair.
Please let me know if you have any follow-up questions.