Default Help with reverting to .8 firmware

Help! I have downloaded the file from asus and put into 3 separate locations. tried a blank sd card and restarted no update in notification bar. Tried putting it into internal storage and restarted... nothing. I then tried to put it into the / file prior to both the sd card and internal storage files and it says "permission denied". I then attempted to scroll down to the file called "/root" and tried to put the file there, It also gives me the error "permissions denied" any ideas as to what i am doing wrong here? Thanks for your help!