http://mirrorbe4n3fxt7qqp7noymyntxe2cfyzumj37t6ah7iu3mpon435cyd.onion/howto.html
Import recipient key: Paste the full public key block, verify fingerprint, then import. Encrypt: Write your message in GnuPG or Kleopatra it's notepad. In your client, select Encrypt and choose the recipient’s public key only. Optionally Sign , your message should now look like encrypted bullshit. thats good now the message is encrypted and can be send.