HTPS (SSL) on Ubooquity server, help needed

I am trying to make the ubooquity server to work with ssl but I am not sure how to start.
As far as I understand, this is a java server and not using any of the installed on DietPI by default.
Does it means that the letsencrypt recommended setup won´t work with it?

Do you have any hints or links I can read to try to make this work?