1. First download Steam Key Generator and Open it.
2. Choose a Game.
3. Click now “generate Key” and wait 10 Sec.
4. Now Copy the Key and Login to steam.
5. Click the Library ► Games menu at the top of the Steam window.
6. Past the key.
7. Follow the onscreen instructions to complete the process.
8. Have Fun!
Its server side and undetectable so You can’t get ban from Steam.You don’t need to put Your email and password. I saw many other fake “generators/adders” they are keyloggers or steam stealers. If You dont believe that this tool is working, and You may think this is scam or keylogger, just make new Steam Account and try this software out