I’m not quite sure what you’re trying to do here. Are you

1. Trying to create a new owncloud instance and put your data somewhere other than in /var, or
2. Try to move the data location of an existing owncloud instance?

If you’re trying to do the second one, there’s a useful guide on it here: omiid.me/…/move-docker-volume-to-bind-mount. The first one should be even simpler, you can just replace the volumes in the compose file by bind mounts (basically, just this step of the tutorial: omiid.me/…/move-docker-volume-to-bind-mount#modif…).