You need to go into device configuration menu, and go to the System/System/Delete Files Policy tab
Here you'll be able to configure
Maximum percentage of occupied space, after exceeding which the deletion of old files will start (Insp.storage)
Maximum number of files after exceeding which the deletion of the old files will start (Event Files)
Quota percentage of file type, above which Old Files Deletion will start (Quota of files by type)