This command will install and run pupcloud, configuring it to:
Use port 8080 (Line 4);
Map a local dir to path /data in the docker environment (Line 5);
Run the server as user/group 1001:1001 (Lines 6-7);
Use free cli arguments, as it was the pupcloud binary (Line 9).
The rest of the lines in this example are standard Docker.
If you specify --follow-symlinks, please be aware that the links are resolved in the docker container, so the feature won't probably work. Use multiple bind/mounts inside /data instead.