Instructions
Power on your Wii console. Allow the system to boot and bring up the launch screen of the system.
Select the Wii Shop Channel by pointing at it with your Wii remote and clicking the "A" button.
Expand the search function and search for "Wii Sports Golf" or a similar phrase that will locate downloadable courses for Wii Sports.
Choose a course or set of courses. Click on your choice and accept the payment request to save the content onto your Wii. The game will read these files off the hard drive to supplement the game disc, which still needs to be in the disc drive.