Calendar sync

[ponsukeen]

Hi,

Newbie here!
I got "everything" installed and "working" on a Ubuntu 16.04 server hosted on Azure (I think).
The only remaining thing is to solve calendar syncing between Roundcube and my Android phone. With another server (with Horde web mail) this is easy "out of the box" as it comes with an obvious CalDav string to copy/paste. How do I get this to work for Roundcube?

Pointers, suggestions?
(All I've googled so far is pretty old - with links to things that seems obsolete).