I just checked again and i found the documentation for the template that i got.
It is the following: https://docs.linuxserver.io/images/docker-nextcloud
In this article the Docker Compose file is written:
"
version: “2.1”
services:
nextcloud:
image: lscr.io/linuxserver/nextcloud:latest
container_name: nextcloud
environment:
- PUID=1000
- PGID=1000
- TZ=Europe/London
volumes:
- /path/to/appdata:/config
- /path/to/data:/data
ports:
- 443:443
restart: unless-stopped
"
I hope that helps