How do I know if the import is working when the process icon does not stop?

When you start the import process, an icon is active at the top left-corner of the CSV import panel.

In case of a large file to import, if you want to know in real time whether Store Commander is truly processing the import, click on the refresh icon of the import toolbar.

The size of the corresponding TODO file should decrease each time you refresh the panel. This means that Store Commander is processing your file.