How to use decision flow in moniter event

Dear all,

I need to do automation on program, At begining I need to search my customer id to find their receipt. If it can find a customer receipt, it will do next step automation. But, if it cannot find a customer receipt, it will show message box, then i need click to close it and then search for next customer. Could you give me some suggestion to find out solution for this problem?

Thank you all

@Kasidit_taechasan Where are the Customer ID’s and receipt stored ?

I stored Customer ID in excel file but receipt keep in server.