Understanding Clay's New Hire Beta Feature and Run Frequency Settings

I've imported in a list of companies into Clay and I'm using a beta feature - Event: New Hire How does this work? Is it running at all times and will add new rows when new hires are added to those companies? I've just opened the table and it says the signal last ran on 28/11 which is the day I set it up. How do I amend the run frequency?