new and in trouble

hello

I am a new player and would like to play this game but have run into some trouble. I downloaded the game which went without a hitch but then when i try to open it via my folder it gives me an error.

Data/enGB/wow-update-enGB-18273.MPQ: World of Warcraft can’t make a required change to an archive file. Be sure you have write permission for the World of Warcraft folder or try running the game in administrator mode. For more information, see: https://battle.net/support/article/6910

Now i am in administrator mode so that can't be it but i don't really see what else could be the problem ( i also don't really get what writen i would need). Could anyone help me wth this