Just figured it is really easy to setup and test a #Nextcloud instance with #docker:

docker pull nextcloud
docker run -p 8080:80 nextcloud
firefox http://localhost:8080/

Also the Android "nextcloud" app is easily installed and can be pointed to the dockerized nextcloud instance if you know what the hostname or IP of "localhost" is in the local WLAN.

More details:
https://github.com/nextcloud/docker