How to receive the lessons again?
I forgot some ideas of one topic. And I want to see some rules that Duolingo gave me before. But I don't know how.
You can always go back and do the lessons over again. Just click on the topic in your tree and then click on any of the lessons in the topic.
If there were rules/tips given before the lesson before, they'll be there when you open up the topic. Under the lesson and above the discussion section.
If there were pop-up tips during the lesson, I think they'll come up again if you go through the lesson again.