How to Switch R4 Skins

1.
Step 1

Connect your R4. Through the USB port (an adapter comes with
your R4) connect your SD card. Press "My Computer" then double-click
on the R4 driver. Open up the systems folder then the themes folder.
2.
Step 2

Download an R4 theme file. You can search for your favorite R4
theme on Google or from an actual R4 theme website. Download and
extract the file (with a .zip extracting application.
3.
Step 3

Click and drag. When your file is extracted, you can drag the
theme into the theme folder and delete your original theme. From here,
safely eject your R4 and place the cartridge into the Nintendo DS.
When you boot up your R4, your new theme will appear.

http://www.gameplayfun.com R4DS, R4i, R4 SDHC, Acekard 2i, CycloDS, DSTTi, M3DS, Supercard DS