Using a Loop Operator to iterate through an Excel file columns

Hi All,

I am very new to RapidMiner. I am trying to setup a loop by which I can iterate through columns of label attributes in a single Excel file. I am trying to process the binomial values in each column. I would like the output to go to a single spreadsheet that contains the processed columns. Which loop operator would be the best to use? How would I iterate through different columns and aggregate the outputs?

Thanks for your help.