You can set up automatic pre arrival email per Program, that get sent to all the participants of the Program, a set number of days before the Program starts.
You can set this up while creating or editing your Program.
Click on the Email tab in the Program, and then click on Enabled in the Pre Arrival Email section:
Then set the number of days before the Program Starts, the Subject and Message of the email.
And then save the Program by clicking Update:
Once a day the system will go through all the Registrations, and see if they need to be sent an email. Pre Arrival emails will only get sent out once per day, at a set time.