Localhost:8080 Good! Now add to existing SSL for HTTPS access?

People,

Firstly - NextCloud is exactly what I want! - I have been watching it for some time but have only just gotten around to installing it for testing - it looks really great! Thanks to all who helped create it . . once I sort out this issue, I can start moving some of my stuff off Google Drive to my own server . .

I got the Docker image installed and running OK for localhost but have had no success getting it going using my existing SSL certificate for remote access. I have nginx setup so that I can access dirs / apps like:

https://domainname.com/webmail

for RoundCubeMail but I can’t see how to install the NextCloud docker image so that I can get remote access to the NC service via https . .

I couldn’t find exactly what I needed by searching on this forum so any help would be greatly appreciated!

Regards,
Phil.