You can find them in the Backup Plan wizard on the Retention Policy step

Yes, I see those settings. Thank you.
I do not think that I explained myself properly.
I am referring to the 'default settings' that would automatically be the 'default' for all future backup plans.

Thank you once, again.

There is no such thing as "default settings". If you want to distribute the same backup configuration to multiple machines, try the Remote Deply tool https://mspbackups.com/AP/RemoteDeploy

Then I am totally confused.
Please see attached.
Thank you.

I got it. Sorry for the confusion. You can edit default settings per endpoint. On the Computers (Remote Management) page, click Edit>Edit Options

Then open Retention Policy