To add a File rename rule expression, perform the following steps:
Go to the Configuration menu → Templates → Expressions.
Click the Add button on top of the Expressions table. You will be directed to the Add Expression - File rename rule page, already filled with default values.
(Optional) Add Localized Values to this expression (for details, see the Add localized values guide).
In the Template field, enter the desired expression template using tags available on the right and/or custom wording.