The files are zipped.
You can extract them with a usualy file archiver.
Each operating system has one or more integrated as standard.
Just doubleklick on the zipfile, choose a place to extract the files and let the programm do it's work.
It only takes a second.
If you really have no file archiver on your os, here are two freeware alternatives:
https://en.wikipedia.org/wiki/7-zip
https://en.wikipedia.org/wiki/PeaZip
"I don't believe in God. I just believe in Billy Wilder" - Fernando Trueba