A test version of GuiloadGX (GuiForwarder).guif goes in the root of your SD card.The guif/theme folder contains all required images, once you open the program you can change the location to whatever you want.
btw i feel this a good time to remind you guys that sea of thieves was made by rare, who also made DKC1-3 and DK64, alongside banjo kazooie and conker's bad fur day