zip unzip attachments in wordpress

WordPress provides a function called unzip_file()— easily found by typing “wordpress unzip” into Google. There is sample code in the Codex:

WP_Filesystem();
$destination = wp_upload_dir();
$destination_path = $destination['path'];
$unzipfile = unzip_file( $destination_path.'/filename.zip', $destination_path);

if ( $unzipfile ) {
  echo 'Successfully unzipped the file!';       
} else {
  echo 'There was an error unzipping the file.';       
}

I have no idea what “custom work” you need to do.