CB Auto Actions is designed to act on triggers. It does not have any form of internal scheduler. For that you have to use CRON and scheduler a task to perform a GET request on an auto actions URL. If you need it to check every user you have to user the Internal Users URL and add that trigger to your auto action, but this will load and send every user on your site through the auto action (it has no batching or filtering at this time) so it can be extremely heavy. Now if you just want to do that email say after the user logins then that's certainly reasonable.