Install acme.sh, or simply `git clone` it into some directory on your MyDevil host account (in which case you should link to it from your `~/bin` directory).
If you're not using private IP and depend on default IP provided by host, you may want to edit `crontab` too, and make sure that `acme.sh --cron` is run also after reboot (you can find out how to do that on their wiki pages).