Things You'll Need
Instructions
Connect the SD card to your computer's SD reader. The card should slide in easily; push it all the way in. You'll hear a click when the card locks in.
Open "Computer" from your desktop or the "Start" menu.
Double-click on the SD card to open it.
Create a new folder named "private" and open it.
Create a new folder named "Wii" and open it.
Create a new folder named "app" and open it.
Create a new folder and name it according to the region you're in.
EU/PAL Region: RSBP
US Region: RSBE
Japanese Region: RSBJ
Open the folder.
Create a new folder named "st" and then open it.
Drag your downloaded custom stages into the folder. Wait until they have finished copying.
Remove the SD card.
Insert the SD card into your Wii.
Start SSBB. You should now see your uploaded stages in the "Custom Stages" section when selecting a stage for the round.