RAR files are archive files which are similar to the compressed Zip files, but are a different format. Within these RAR files is the content which you can then import so you need to extract the contents from the RAR files first.
To un-RAR or unzip these files, you can use 7zip, which you can get here:
If you are using the 64-bit version of Windows, download and use the 64-bit version, though the 32-bit will work as well on that version. If you are using 32-bit Windows, you can only use the 32-bit version.