There are two things that you need to do here. First, create a list of files you want to move around. That's done by globbing: @list = <*.puz>.

Than you'll have to rename that file to add the 'A' and move it at the same time, the first part is done by regexes, see perlre: s/(\.puz)$/A$1/; and the second by concatenation: $name= 'subdir/' . $name.

You'll have to rename every file, so loop over your list with for:

for my $new ( <*.puz> ){
  my $old = $new;
  $new =~ s/(\.puz)$/A$1/;
  $new = 'subdir/' . $new;
  rename $old, $new;
}
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