In Source you select the format you would like to import. Since we are importing CSV, you select CSV here.
Once you have selected CSV, you can attach the file you would like to import by clicking Select File.
If the file is a valid CSV, you will see a picklist to select the delimiter used in the CSV file.
Select one of the following options depending on your CSV file:
Tab
Comma
Semicolon
The button Next will not be available if the selected file is invalid.
Click Next to proceed to the next step.