Thank you very much for your help.
At least at first glance that seems to have worked.
In the output it says:
These files will be updated when the certificate renews.
Certbot has set up a scheduled task to automatically renew this certificate in the background.
That sugests I don't need to explicitly set up a timer or cron job to renew.
Do you know if that is the case or is this talking about something else ?
Do you know how it has set up that task ?