How do I close my books for December so I can see my total sales etc?

Hello sandy48,

You can close the books at a specific date which will mean a warning message will appear when any transactions are added with a date prior to this. 

To do this, go the the Cog Wheel > Accounts & Settings > Advanced > Accounting > Select the option to 'Close the books' and enter a closing date. 

When running reports, you also have the option to enter a custom date range to allow you to view total figures from specified periods. 

Thanks