For opening or extracting zip files you don’t actually need any program. There are several ways to do it so I will show you a bunch of them so you can use the one you prefer.
Opening zip files with 7ZIP
This is a free program called 7zip:
And here you have some tutorials on youtube:
Opening zip files in Windows 8
Opening zip files in Windows 7
Opening zip files in Mac
I hope this helps! Thank you!