How do I use a periodic trigger in Automagic? There's an app called Automagic which uses flow charts to create workflows that let you perform custom sequences of actions on your Android (essentially macros, but with an advanced interface for editing them). 

Can somebody please explain how to use the periodic trigger? 

I've tried using it to kick start a flow, but it never fires. I've ensured that the flow is enabled, I've checked the logs and there's nothing about any problems occurring with launching the flow.
You must enter the time. For example, if you want it to be every 5 seconds you need to write "5s".