itch.io

I'm not sure. There should be a link to claim a game you both. If I remember the instructions correctly, you'll see it if you go to the game page from the bundle page. Hope this helps!

Just click the download button from the bundle or store page it will then show up in the library. You don't even have to download it. The way the bundles are setup is so you see it in the bundle only until you click download for the game to prevent libraries getting mass flooded with items you don't care for.