i have this problem: i want to sum all the sales of one person but occurred many times using the SUMIF function. But i am not sure how to do it since i am new to using this function. i have tried this formula: =SUMIF(Sales,COUNTIF(Name,Sales),Name) but i am not sure if this is right

For example:
Name Sales Region Commission Rate Commission
BERNIER $171,904 central 4.80% $8,251
BERNIER $171,904 north 4.90% $8,423
BERNIER $171,904 north 6.30% $10,830
BERNIER $171,904 north 6.00% $10,314
BERNIER $171,904 south 4.40% $7,564
BERNIER $171,904 west 4.50% $7,736
BERNIER $171,904 west 4.50% $7,736
BINCE $162,605 central 5.80% $9,431
BINCE $162,605 east 4.60% $7,480
BINCE $162,605 east 4.60% $7,480
BINCE $162,605 south 4.10% $6,667
BUSHBY $200,448 east 5.40% $10,824
BUSHBY $200,448 east 4.10% $8,218
BUSHBY $200,448 south 6.20% $12,428
BUSHBY $200,448 south 6.20% $12,428
BUSHBY $200,448 west 5.40% $10,824
BUSHBY $200,448 west 5.10% $10,223
CAMPBELL $259,500 north 4.30% $11,159
CAMPBELL $259,500 north 6.20% $16,089
CAMPBELL $259,500 north 4.30% $11,159
CAMPBELL $259,500 south 5.20% $13,494
CAMPBELL $259,500 south 5.20% $13,494
CAMPBELL $259,500 west 6.20% $16,089
CAMPBELL $259,500 west 6.30% $16,349

Can anyone help me with this problem?

Thanks,
roter