There are two types of timers to choose from when setting up your Automated Message Campaign (AMC): 

Based on days (evergreen) is the most common. Choose this if you want to send messages based on the number of days after a person has entered the campaign. (ex. messages will be sent on the 1st Monday after the person texted, was added to a group, or completed a data capture - depending on which triggers you have selected). This article has more information: https://help.pastorsline.com/en/articles/2793118-v3-how-to-use-the-send-after-x-days-condition-in-an-automated-message-campaign

Date-based (one time use) is only if you want to use this campaign one time. This is date specific and after the date has past, it will no longer work. (ex. messages will be sent on December 1, 2, 3, 4, etc.)

For on using and creating AMCs click HERE .