Budget Question

I am starting a new year (2009). I have created the new Periods but waht do I do about the main Budget for 2009. Do I create a new main Budget or is this something that the system does? Also if I do not want to setup a new budget for 2009, can I use the same 2008 Budget for comparison? Please specify which SAP option do I use to create the default Budget for 2009.

thank you

Robert