.7z files are archives (like .zip or .rar). You can extract them using WinRAR, but it’s an old program that you should pay for if you don’t have license.

On the image below is 7-ZIP version you should download if running Windows (or rather where you should click because version will probably be newer in the time you read this).

Other than downloading correct program you shouldn’t have problems while extracting files. If you still have a problem, you can leave me a DM!