Help with formula maybe Sumifs?

Hello all,

I hope someone can help me out. I would like to calculate the return rate for my orders for an online shop of a month (e.g. April).

However, since customers have 30 days as a return period, the returns and the orders are not comparable the same but delayed.
I have 2 raw-data spreadsheets: 1) April orders 2) Returns from April to June to catch all returns to April orders.

Both spreadsheets contain 3 columns: 1) Order number 2) SKU 3) Quantity.

Now in the third sheet ("Dashboard") I want to calculate the return rate for April.
Now I am missing the formula for column C in 'Dashboard'. For this, I need a formula that outputs the sum of the returns (column C 'Returns April-June'), but only those that are existing in the April orders.

All orders from April and all returns that refer to an order from April have the same order ID.
This order ID can be used to link/compare the orders and returns.

So again in short:
Criteria:
Sum of column C in 'Returns'.
Range: Column B 'Returns
Search criteria: A2 'Dashboard'.

But only if column A in 'Returns' and column A in 'Orders' are the same.
Attached is a sample file: Ret_ENG.xlsx

Thanks in advance!

Hello
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