Hello,
I created my first minimalist public collection - you can see it here:
Your opinion is welcomed! 
But I watched collections of other authors and saw that they have a rating stars. I liked several collections and I wanted to give them a rating too, but I did not find out how it can be done.
The question is: how I can rate the public collection of another author?
Thanks to everyone!
It looks like there’s an option to rate the collection at the right hand side of the collection page. You probably can’t rate your own collection though, especially as it only contains your items.
@SpaceStockFootage , thank you for responding!
No, I don’t want to rate myself… 
I found the answer.
I’m looking at a list of collections in “sign in” mode. But when I open a collection in a new tab (chrome) - I do not understand why, but system shown that I have not joined. Therefore, I can not see option to rate the collection.
Have a nice day!