Hi LitteHikaru,
If you are using a smartphone or tablet, you will see a grey field with a winner’s podium under the green "PLAY" button on the left. Tap on it to view the rating. 
If you are on a PC or Mac, you'll find the rankings on the right side of the start page for GO:  

https://www.flyordie.com/go

  .  
Only players with a premium subscription are listed in the rankings.

Kind regards, John