duplicate a nest - change 2nd nest contents without changing first nest

This is frustrating the absolute hell out of me - running premier pro v23.4 (latest version) and have gone though all the comments relating to this and no matter what I do i'm left with the same outcome...! I have a nest in a timeline, I locate the nest in the project list - I duplicate and that's where it goes awry somewhere, have renamed the new duplicate to something else and dragged back into timeline, edited it's contents as needed and go back to the first nest and it's changed that too... You would think for something so simple there would be a much easier option!? Can someone please shed some light on what i'm doing wrong as i'm literally pulling hair out here every time I change the duplicate nest only for it it to change the original

 - The frustrating thing is, is that I have gone through all the discussions on here to absolutely no avail