Data analysis

would like to analysis which clients stopped purchasing, which clients has slowed purchasing etc. for each month we have the sales figures, and the amount of orders placed, as well as gross profit for each month (Around 505 clients each month). Would you be able to organise this excel sheet, and prepare a simplified version, with a calculation to show these clients? Berechnet=Sales ( we only need to use this figure, as well as amounts of orders placed9 I am pretty good with excel, however currently dont have the time to manage this.