Finally, there is a Rating data type that you'll encounter if you're using recommendations with MLlib. This data type can take in a rating that represents a 1-5 or 1-10, whatever star rating a person might have, and use that to inform product recommendations automatically.
So, I think you finally have everything you need to get started, let's dive in and actually look at some real MLlib code and run it, and then it will make a lot more sense.