Once you've downloaded all your files, examine them. All the files should be the same size, except the last. They will have numbers after them such as "part1.rar" , "part2.rar" , etc. Place these files in a folder.

Now select the RAR "part1.rar"

Right Click on it, and the dropdown should give you the option to extract to ****\ assuming you have already installed WinRAR.

Select extract to

And when finished extracting, you should have a new file.

Open the file, and in it should be the completed extraction of all the file parts as you can see by the file size

Finished!