Something like this?

use strict;
use warnings;

use File::Find;
use Data::Dumper;

my $dir = '/TC/APR-TCCC-0003/APR21-TCCC-0003';
my $dataSet = [];
find( 
    sub {
        if( -f ) {
            push @{$dataSet}, $File::Find::name;
        }
    },
    $dir
);

print Dumper $dataSet;
[download]

Or did you mean...

$dataSet = $dir;
[download]

Please follow up with clarification as to what you mean by assigning into $dataSet a directory structure that has been assigned into $dir. The lack of clarity of the question will probably cause us to all miss the mark in our replies.