Any idea where my thinking or implementation is wrong?

That's simple. You have declared the variable as our in your module, but not in your script using that module. For something to be labelled as our, there must be at least two of them sharing it. So, saying

use lib 'F:/scripts/perl/';
use junk;
use strict;
use warnings;

our $variable1;

print("\$variable1 = $variable1\n");
[download]

will fix that issue.

Note that our variables are lexical aliases for a package variable. So, if the lexical scope spans several packages in the same file, all of those packages see that (unqualified) variable, which is a global to the package that declared it (I think of our as an autovivification of package globals):

use strict;
package Foo;

our $bar = "guggug!\n";

package main;

print $bar;
__END__
guggug!
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_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}