Sharepoint workflow - how to send notification based on date field

Hi -

I am new to sharedpoint and am trying to create a workflow that sends an email notification 3 days before an expiration date.

I have a database and have created a colum for Reminder date (expiration - 3 days). This is calculating fine. I would like the workflow to automatically send an email when the reminder date is reached. I have set it up in work flow as a run if: the reminder date equals (ignoring time) the workflow contntext "current date", then send the email. It seems simple but each day I come in there is no email.
See attached

Also, is there a way to make a workflow run automatically each day?

Chris