I’ve had to try and get this working a few times now, and every time it’s a major faff as it’s not officially supported yet, for some reason.

After an awful lot of searching and trying a lot of different methods I’ve finally found one that seems to work and is straightforward:

wget https://dl.eff.org/certbot-auto

chmod a+x certbot-auto

sudo ./certbot-auto --debug  --server 

https://acme-v01.api.letsencrypt.org/directory   -d domain.com 

Then just follow the instructions and bask in the joys of Certbot and add it to cron to autorenew.