Uly, по вечерАМ - at nights ?

We don't use the plural like that.

So, it concerns "in the evenings" too? Do you say on Tuesday nights, for example?

Yes, you can say ON TUESDAY NIGHTS. But if your referring to a time of day in general, you use the singular: I'm always hungry in the morning. Helena usually goes jogging in the afternoon. We always watch movies in the evening. Andy never reads at night.

One exception is that sometimes people say "she doesn't sleep nights" which means that she's an insomniac, or that he's worried about something. But when you question somebody about their conscience, you say "How do you sleep at night?"

Thank you! Got it. I didn't know about that.

👍🏼