Right-click on the zip and click "Extract All..." and follow the prompts.
A new folder will be made with the game files inside.
Launch the game with "Among Us.exe"
WinZip is pointlessly paid software, uninstall it if you can. 7-Zip is a free one you can get if you need to extract from 7z or RAR files. However, you don't need any extra software to extract from zip files.