How do Date Rules work on programs

Those are date automation rules and allow dates on an account program to be set automatically based on the value of other dates. This only takes effect if the "auto" checkbox is checked. Then in the target field, enter the ID of another date (the ID column in your screenshot, 1 through 12). In the increment field, set how far forward or back you want the date to be relative to the target.

Example: Set the Service End date to have a target of 11 and an increment of 28. 11 is the ID of the Service Start date. When someone in that program sets someone's start date to a value and saves the account program, the automation rules run. The rules will set the end date to the value of the target (the start date), incremented by the increment (28, in this case 4 weeks). If I set someone's start date to 1/1/2025 and saved, the end date would automatically get set to 1/29/2025