Now, everyone can rate each other's game. See the video for how to rate

You have to choose any game and click on the view game page and on the top right there will be an option to rate that game.

No bro, this is not rating for game jam but rating for Game that is on itch.io just like you rate games on playstore

Rated jams look like this

yeah this is not known as rating for the jam it is just a itch.io rating system