We tried to make OpenKM as intuitive as possible, but an advice is always welcome.
Forum rules: Please, before asking something see the documentation wiki or use the search feature of the forum. And remember we don't have a crystal ball or mental readers, so if you post about an issue tell us which OpenKM are you using and also the browser and operating system version. For more info read How to Report Bugs Effectively.
About the "experimental feature", take as is, if you are outside Amazon, we do not recommend use S3 storage due the bandwidth is needed to get running for getting an acceptable performance.
This mean is an experimental feature, what seems only we have done some tests with repository export. If you want to play with it, review the class named FSDataStore and from there with few changes you also will be able to point the datastore to the S3. There are two variables "fs" -> file system and "db" -> database you should create a new one "s3" and apply few changes.