If you select the SAVE option under the Design Mode menu, you can save one of your original courses. You can only save one course at a time. If you save a second course after saving a first, you will overwrite the first course. Be careful! Data that is overwritten cannot be recovered.

About Saving
When saving your game, please be aware that any of the following actions may cause you to lose your save data. If you lose your save data in any of these ways, there is no way to recover it, so please be careful.
While data is being saved, pressing RESET or turning off the power on either the Wii console or Wii Remote.
While data is being saved, selecting either the Wii Menu or Reset options from the HOME Menu.
Disconnecting the Wii AC Adapter from your Wii console while it is turned on.