RAR files are compressed archives (just like zip files) that contain any number of parts and any kind of user generated types of files, from video files, audio files and beyond.
To decompress these RAR files and gain access to the files inside, make sure that you download all the parts (.r01, .r02, .r03, ...) and then use WinRAR to extract the files.
Get WinRAR Here
Many users have reported that 7zip works interchangeably for extracting RAR files.
Get 7zip Here