Hi Marky
I presume you are creating the Sales Receipt or invoices/invoice payments relating to the payments. You can view and filter the all sales page to get a total of sales within a given period; Select sales>all sales>filter>in status select paid>then enter the date range you require.
You can also run a sales by customer detail report or if you are receiving the payments into a specific cash chart of account you can also run a report on the chart of account, select accounting>chart of accounts>to the right of account history there is a drop down arrow>select the drop down arrow/menu and select run report>then select a date range>run report.
