lg vx8100 MIDI sound

I downloaded a MIDI (I think????) sound from Yahoo but I have no idea what to do with it now as it was put into "my sounds" on my LG vx8100 and I can't make "sounds" into ringtones or alerts or anything. What can be done? Please be specific as I am a newbie with all this stuff. By the way I don't have a USB cable but I do have a memory card. Thanks

you will need the usb cable to do it you can find one at verizon store or get one of .99 on ebay