RAR files are a special kind of format called an archive. Archives store other files within themselves. The files compressed inside of a RAR archive can't be used until you "unzip" them. Software available online will let you unzip files, a process that can take a few moments depending on the size of the archive.
Navigate to Wobzip (see Resources). Click the "Browse" button to select your RAR file and upload it to the site. Click "Wobzip!" Click the links to your unzipped RAR files to download them.
Download and install WinRAR (see Resources). Right-click the RAR file. Select the "Extract here" option with the WinRAR symbol on it. The files unzip to that location.
Download and install WinZIP (see Resources). Double-click the RAR archive. Click and drag the unzipped files that appear in a box to where you want them on your computer to unzip and move them to the Desktop or desired folder.