./letsencrypt-auto certonly --manual --preferred-challenges http -d huntrods.com
and created the required file on my apache server in the correct (acme-challenge) directory. After pressing ENTER to continue, I got the success message:
IMPORTANT NOTES: - Congratulations! Your certificate and chain have been saved at: /etc/letsencrypt/live/huntrods.com/fullchain.pem Your key file has been saved at: /etc/letsencrypt/live/huntrods.com/privkey.pem Your cert will expire on 2019-03-07. To obtain a new or tweaked version of this certificate in the future, simply run letsencrypt-auto again. To non-interactively renew *all* of your certificates, run "letsencrypt-auto renew" - If you like Certbot, please consider supporting our work by: Donating to ISRG / Let's Encrypt: https://letsencrypt.org/donate Donating to EFF: https://eff.org/donate-le
So it all worked the first time manually. Thanks again to all for your patience and help.