In AN12597 zip file there is IAR and MCUXpresso directory. In both there are "k32l2b3_usb to multi vcom.zip" and "k32l2b3_usb to multi vcom_optimized.zip". In IAR directory (zip files) I can't find workspace file and don't know how to open it. In AN12597 pdf there is ...
There is note that "two similar projects were also provided for K32L2A", but I can't find it in AN12597 zip file.
Unfortunately, this application note does not support IAR. As you observe in the .zip, sadly there is not a workspace file (.eww) in any of the project folders; the folder IAR is sort of a copy of MCUXrepsso folder.