you don't have to pay. also use 7-zip or just any extraction tool and extract the file you've downloaded (right click > extract to...) and there should be a file for the game.
well it should be the extact same as long as you can access your downloaded files.
also heres a download link for "7-zip" like i mentioned earlier - https://www.7-zip.org/download.html
Once 7-zip is installed, right click on the downloaded file for THIS game, and click extract to [INSERT GAME NAME HERE] and then open the extracted file and you should find the game there, if you do see it, open it and you're good to go.