To create a time transformation, select "Add → Time Dimension" from the diagram context menu.

As shown in the image below:

The Time Transformation Wizard will then open, allowing you to configure a new time transformation:

Parameters

1. Schema
   The schema in which the time transformation resides.
2. Name
   The name assigned to the time transformation.
3. Period (Minutes)
   The interval (in minutes) used to generate time dimension records.
4. Time-to-ID Function
   The macro function that converts a DateTime value into the key value for the time dimension.
   Use case: Convert datetime fields in fact transformations into time dimension members.
5. Stars
   The data mart stars where the time transformation will be included.