I re-created your data with Clients, Product, Qty, Total in cells A1 to
D1, and the Roger-Lynda-product-qty-$ data in A2 to D7. Then I created
a summary section with the headers in G1 to J7 that looks like this:
Client__Product__Qty__Total
Roger___product1_5___200
Roger___product2_0___0
Roger___product3_0___0
Lynda___product1_1___40
Lynda___product2_1___50
Lynda___product3_3___120

(Great idea to use underscores, btw!)

I used this formula in I2 to sum the product quantity by client:
=SUMPRODUCT(--(G2=$A$1:$A$10),--(H2=$B$1:$B$10),$C$1:$C$10)

....and this formula in J2 to sum dollars by Client by Product:
=SUMPRODUCT(--(G2=$A$1:$A$10),--(H2=$B$1:$B$10),$D$1:$D$10)

Copy those formulas down through J7. Also please note that Excel
considers 200$ as a text string, not numbers; enter it as $200.

And no worries, your English is excellent!