Copy the rules_examples and create your own rules folder. The rules folder represents the File provider. By mapping the File directory to this folder you can easily manage and organize the dynamic configuration for the File provider. The watch flag is on by default, so changes made to these files will update in real-time. You can set the watch flag to false to stop this feature.
It is also possible to create sub-directories here to further organize things, however the watch function doesn't seem to work on files within the sub-directories.
Create a file in the acme folder called acme.json, and assign the correct permissions:
$ touch /path/to/acme/acme.json
$ chmod 600 !$