Download MARX.7z.

Open/Extract the .7z archive. You can use 7-Zip to do this.

Create a Skins folder in the root of your flashcart’s SD card.

Inside the 7z archive, you will find a folder called MARX.

From this folder, copy MARX.skn to the Skins folder on your SD.

Place the SD card back into your cart, and launch Moonshell 2.

In Moonshell 2, navigate to the Skins folder and press A on MARX.skn to apply the theme.