Define which files should be purged and under what conditions.
SCREENSHOT
Purge when number of files exceeds
Start purging files if the number of files in the selected folder exceeds the specified number, until the number of files in the folder equals the specified number (50 in the above screenshot). You can choose between purging oldest files on Modified date or newest files on Modified date.
Purge when file is older than
Purge files that are older than the specified number of Days / Minutes.
Run schedule
Choose how frequent and at what times the folder contents should be checked against the schedule settings.