Download certbot
$ wget https://dl.eff.org/certbot-auto
$ chmod a+x certbot-auto
Generate Certificates
sudo ./certbot-auto --debug -v --server https://acme-v01.api.letsencrypt.org/directory certonly -d YOUR_WEBSITE_HERE
Auto Renew Script:
sudo crontab -e
0 1,13 * * * /home/ec2-user/certbot-auto renew