He was referring to the games list icon on the top banner in USBLoaderGX, make sure "Wii games" is checked, if everything's correct your Wii games will show up.
Ntfs should work for Wii games, but not GameCube games (need fat32). Make sure your usb is plugged in port 0 (lower port when Wii is sitting horizontally). Also check the settings on usbloadergx and see if the usb drive is set to port 0 not 1.
"Wbfs" files are harmless, Morningglory was talking about "wad" files 'cause they have to be installed on the wii to be read/ used, if you install any random wad out there without protection, if it turned out the wad was corrupted, your wii is bricked.
By protection im talking about BootMii, Priiloader and a nand backup image. Since you mentioned Wii.guide site, I'm assuming you followed their guide to mod the wii correct? If you installed bootmii, Priiloader and have a nand backup you can install wads, atleast from known/ trusted sources..
How did you format the flash drive?
Also you didn't answer any of my questions above. you seem to be just a kid, that's why im doing what i can to help you..