Help please with using Webdav server reource on cloud

I am hoping to use a webdav server in order to share a private calendar on our network without using google. I have access to a Webdav server through my cloud account (pCloud) so I am hoping to use this.

I have confirmed that the Webdav service is available and can log into it but this only shows me the directories already installed on the cloud account and does not give any clues as to how I may add a directory which can be shared using webdav.
So far I have been unable to a folder on the webdav server either from browser or using Dolphin.

If I add a calendar in Thunderbird I cannot create and save an event because I get an error and the calendar is shown as read only.

Please could somebody direct me to required reading to get me started.