WBFS tutorial for dummies like me

[parley]

after a bit of searching around on here i'm sort of getting the gist of how to play NSMB via usb loader or wiiflow, but when i try to get my iso file which is over 4gb onto my usb drive via WBFS i just get an error message saying something like "not a system command"
any steps for a simpleton like me would be greatly appreciated, i have a nine year old itching to play this game.
many thanks.

[parley]

after reading diddy daves above post and downloading WBFS manager i have now got that bit sussed, many thanks diddy dave.

[Seasider]

Just upgraded to windows 7 and WBFS manager does not seem to like it. It runs ok but will not aloow me to add any games