First of all iOS 6 and Tinder and are two different things.
iOS 6 is the operating system that runs on Apple's iPhones. There have been more updates on that software and it is now on its version 7. Version 8 is to be launched this Fall.
Tinder is a dating app that uses data like photos and interests from your Facebook profile to create your own profile others on Tinder will be able to see and judge.
To judge, one has two big main buttons to press: the "cross" button to indicate how you are not interested in seeing more of the profile in front of you and the "heart" button which once pressed will inform the owner of the profile you just liked that someone is interested in them.
The good (this is debatable) thing about Tinder is that others will only know if you like them if they like you back. Also you will never know if someone didn't like you back as the app conceals this by not connecting the two of you.
If you feel like knowing how Tinder works, check my other answer here on Blurtit: