Setup

Paycheck Planner Setup page has a few controls to easily set the parameters for your projection.

Select Calendar field should list all calendars the logged-in user owns. Leaving calendar unselected will result in errors in the Plan and Monitor page.
The initial balance is the amount of money you have at the beginning of the selected period of time.
Initial and end date fields set the period of time to run projection for. As expected, the initial date must be before the end date