how to use break by statements in a nested for each loop with three tables in progress 4gl

I am fairly new to progress. I am trying to figure out the working of a nested for-each loop. Suppose I have three tables Customer, Order and Orderline. I would like to use break by on these tables based on customer.customer-num and Order.ordernum to generate a final report. This is the code I have so far.

for each Customer no-lock,
each order where
order.custnum = customer.custnum no-lock,
each orderline where
orderline.ordernum = order.ordernum
break by customer.custnum
by order.ordernum:

if first-of(customer.custnum) then do:

put stream s1 unformatted

space(3) customer.custnum format ">>>>9" space(1)
customer.name format "x(30)" space(1)
customer.city format "x(12)" space(1)
customer.state format "x(20)" space(1)
customer.country format "x(20)" space(1)
/*order.ordernum format "zzzzzzzzz9" space(1)
order.orderDate format "99/99/99" space(1)
order.orderStatus format "x(20)" */ skip .


end.

put stream s1 unformatted

space(95) order.ordernum format "zzzzzzzzz9" space(1)
order.orderDate format "99/99/99" space(1)
order.orderstatus format "x(20)" space(1).
end.

if first-of(order.ordernum) then do:


put stream s1 unformatted

orderline.linenum format ">>9" space(1)
orderline.itemnum format "zzzzzzzzz9" space(1)
orderline.price format "->,>>>,>>9.99" space(1)
orderline.qty format "->>>>9" skip.

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