Decision Box - Need Help

I need Decision box to skip steps if the value from CSV file is blank, but unable to do so can someone help

I have a CSV where i have a Field 1,2,3,4 & 5 and would like to check if field - if Field 3 = Blank mark it as True and follow next Sequence like wise if False Process the Step.

While i tried to use decision box I’m unable to find Field 3 which is row as per CSV Datatable type, can someone please help.

Please add your sample file here