How it works is that they learn about what kind of product or service you have and your goals in mind. They do a search for an ideal candidate(s) for your position and in a couple of weeks or so they have five candidates in mind. In preparation, they allow you to utilize the tools they have such as how to interview, contracts, etc. and once they are delivered to you, you're ready to interview and proceed further.
This is a great place for you to find qualified candidates instead of an influx of applications for those that are not ideal for what you need. It only takes an average of 12 days from start to finish and that's time-saving benefits that you can use in other aspects of your company.