2 fields for 1 product showing something else

Hi,
how do you set up for one product to show two fields but each should show something else. f.e. in first field we want the cx to choose what is the lenght he/she wants from that product and above where the price is it is calculating what we wants. This is what we were able to do, but we want in the second field, below the first field to show how many meters square cx is actualy buying. It that even possible with this calculator ? Thank you for any advice.