Another thing you can do is look at the certified workflow "NFSv3 File Access". It uses a table to collect as user input 1 or more export policy rules. Then it uses row repetition to iterate over the export policy rules user input table to create the export policy rules on the storage system.
This workflow is a good example of getting the size of the user input via the 'getSize' function, and then the 'getValueAt2D' function to get the field of the user input line needed for that particular command block parameter.