Working Hours defines the parameters of what to do to the computer when idle time is reached during working hours that you define.  

The System tab describes what happens to the mechanical parts of your computer after a period of idle time. 

The Options tab defines various options for ShutdownPlus Green.

The Electricity/CO2 calculator will calculate the maximum savings you can obtain if the computer is idle for the entire day.

The top part of the tab lets you define how many watts your computer uses.