Back up a bit, perhaps. Do you understand that files with a ".rar" or ".zip" ending are compressed (condensed) files, packed to take up less space when moving. copying, etc... ? Compressed files cannot do anything alone. To use the file, you have to "unpack" it first. That requires, as stated above, a program to unpack it, There are may free ones out there. Win zip comes to mind. Many are good. Some handle more than one compression type. Almost every site you go to to download the free version will try to get you to "buy" a 'better version." For what we do, the free versions are more than adequate.
You download and install the unpacking program, unzip, whatever. Once it is installed on your PC. The compressed "rar" "zip" whatever, will recognize the unpacking program and un-zip to wherever you tell it when you double click on it. Once unzipped, you will have files in folders. These folders are what you move into the EWoM mod folder. Hope this helps.