Where incremental backup?

This box do it full backup instead incremental backup.
For me need 1,5 TB incremental backup to 1 day and sync backup on week.
But it not work!

link for problem - link to google drive images

Hi systemn17088,

Each incremental backup copy and it’s contents will reside in a time stamped directory structure. Moreover, it does not only backup files that have been changed or modified since the previous incremental backup and the entire content is saved to a different directory. For more information, you can refer the link given below.

https://support-en.wd.com/app/answers/detail/a_id/20227

OK, but what is the difference between incremental backup and full backup?