But my samples, obviously, are located in the same place they have always been on my HD.
What is the correct way to direct Push to my sample library?
Surely I don't have to move my whole sample libraries location, nor duplicate it?

As far as I know, the default Samples folder in your User library is for sounds that have been incorporated in instruments (drum racks, instrument racks) that you have saved in your user Presets. So for example: I like the Sonarte found objects library. Every time I make an instrument based on e.g. the Garden Fork, the Plastic Bucket, or the Wadded Tampon, that sound gets saved in my User LibraryOK - I can see that there is a 'Samples' folder in the User Library sub-directory.
But my samples, obviously, are located in the same place they have always been on my HD.