please note i have performed all the step provided by you , but still its not showing total quantity against each invoice of each customer

i have shared screenshot for ur convenience , please note i note i need to know total number of item quantity

for ur understading let me elaborat it more with screenshot

like my customer name is malik time cosmetics

two invoices are issued 

invoice no :3213 and 3820

i want total quantity for invoice 3213 which  24+2 = i need figure of 26

and amount 1764

and invoice 3820 12+1= i need figure of 13

and amount of 1528

in simple subtotal of amount and quantity against each invoice , if not possible for each invoice atleast for both of them total no of quantity sold and total sale which is already showing