I'm assuming you mean 'Office 2013' by 'Windows 2013'. There is no point in putting them in the MSOffice15 folder.
Open Explorer (Windows key + E) and paste the following in the top bar
followed by an enter. That should get you to a directory.
Go down the directory structure Microsoft => Bibliography => Style. If one of those subdirectories does not exist, create it.
Put the files in the Style directory.