Installing the downloaded files is quite simple.
After you download the extension from www.hdflvplayer.net follow the below
Steps to install this module on your Drupal6.xx website.
1. Open the downloaded package, in which you can view the folder ‘hdflvplayer’.
2. Copy & replace the folder ‘hdflvplayer’ on your root folder.
This would be the path: www.yourdomain.com\sites\all\modules
There you go! The module is installed perfect now!