I installed it but cannot see where to begin?

https://www.ads-software.com/plugins/wp-sweep/installation/

Hello Lester,

Thank you very much for your quick reply.

By the way, I used it to sweep everything, but duplicated posts still exist:
https://teletravail.info/thu3/

Could you advise me how to delete those duplicated posts,please?

Regards.

That means something is still creating the duplicated post on your end? Maybe plugins? Like for transient options, once you deleted, the same number will come back again because WP recreates them.