The run import tab is where you configure what records should be imported using and any template specific settings.
The start row field allows you to set the starting record.
Number of rows
The number of rows field allows you to set what range of records should be imported.
The run now radio button, will trigger the importer to run when you click the Save & Run button.
This will load up a modal that will process the import file, and start the import.
Once the importer is running the modal will display the progress of the import, with a progress bar and stats showing how the current import is getting on, and a log at the bottom showing all the records that have been imported so far.
You can pause the current import by clicking on the pause button, this will stop the import and allow you to continue it.
Click on the cancel button stop and cancel the current import.
The schedule radio button will allow you to run the importer on a schedule.
Schedule to Run
Select how often the schedule will run (monthly, weekly, daily, hourly).
Check this to disable the schedule temporarily.