When access cell quantity then press enter go to Last Empty Row then focus First cell(Code) in Datagridview

Problem

When access cell quantity then press enter go to Last Empty Row and focus on First cell(Code) in empty row .

meaning i need move from current row to last empty row first cell focus of Code on that empty row

details

I have datagridview have 4 column 

Code 

NAME

Quantity

Price

Code  Name  Quantity  Price
122   pen     5        12
EmptyRow

Actually i need when access cell quantity that have value 5 and click enter go to next row empty that already exist

and focus on cell code

How to do that please .

I need when access cell quantity then enter not add row only focus to empty row first cell code and focus on that cell

the empty row already added after every reading by barcode machine .

it take too much time to move by cursor mouse from first row to next row first cell focus 

so that this rapidly .