There is a bit of nomenclature here that is not working in your favor. Perl does not have a concept of "pointers", although it does use "references" a lot (there is a not so subtle distinction - in Perl objects are reference counted). Perl allows references to pretty much anything, including references so you can have what may be considered indirect references, but they still ain't pointers.

I suspect a good dose of reading is what you most need at this point. Take a look at perldata and perllol. You may find the Tutorials section Data Types and Variables helps a lot too.

Assignment always replaces whatever was previously contained by a variable. It doesn't matter what "type" of thing the variable previously contained, it gets replaced.