You can define your review cycles in the Review Cycles tab of your Manage Account page. To get there in the application, select the Manage Account option from the left menu (under the Settings section). Once in the Manage Account page you will see a tab titled Review Cycles.
To define a new cycle, fill in the details (name, start date and end date) in the empty row and then hit "Save". To add multiple cycles at the same time, use the "plus" icon.
Note: As of October 28, 2017 it is no longer required to enter a start and end date.
You will also notice there is a checkbox for Goals. If you are using our goals module, it is likely that there may be certain review cycles which you may not want employees to use. Be sure to uncheck those boxes. For more information on goals/review cycles, refer to Evaluate an employee's goal progress.
For more information about Review Cycles, please refer to Understanding review cycles.