how do I know if a game is rated or unrated


It will actually say if a friend is challenging, for example "5 mins-unrated"
You can challenge other people on their profile on the "challenge" option and you will see an option for rated or unrated.
When you get to live chess:
In open challenges, green dots mean rated and gray dots mean unrated on the chart
In create challenge, there is an "rating" option. Unrated or rated, you can decide!
I hope that helped!