MoP download help

ok im generally rather inept at this type of thing. i downloaded the MoP expansion over night and put all the folders into a vanilla WoW folder i had from a previous server i went on and nothing works. ive replaced the realmlist files and ran the application as an administrator but no dice. please help.

from where did you download MoP expansion?
If from here: https://www.warmane.com/download then just click on wow.exe ( you do not need to move any file inside any other old "WoW client")