Easy, just go to http://www.gomlab.com/eng/ and download the latest version.
There is no users manual for GOM player but it is well worth spending the time to explore its settings menus. GOM player has the most extensive sets of controls of any medial player I've used.
If you click on the GOM logo in the top left of the player and drop down the menu, you will find About GOM player and a URL for the Forum web site where users post information about using it.
