The strict order in the interrogative sentence is relevant for fully-fledged questions:
Can you play the piano? - Умеете ли Вы играть на пианино? or Вы умеете играть на пианино? (Stress on "умеете")
You can play the piano? - Вы умеете играть на пианино? (Stress on "пианино") This sentence conveys an element of surprise and asks for a confirmation - see explainsthefunny's earlier comment.
In fact, "умеешь" is "you (singular) know"; "to know" is "уме́ть".
https://en.wiktionary.org/wiki/%D1%83%D0%BC%D0%B5%D1%82%D1%8C#Russian is quite clear that it can mean both "to be able to" and "to know how to". Quite different from "Знать" which just means "to know" in the sense of "knowing stuff".
I agree. I is not a litteral translation of this sentence but was the first to come to my mind. Although, you can have knowledge about playing piano but don't play it regularly. In that way, there is a difference between 'can you play' and 'do you play.' Still, I think it should be accepted.
Just a general comment, but the intonation of this sentance is wrong. It sounds like a statement, rather than a questuon. In general most of Russian sentances in this course are pronounced with incorrect intonation. There is a very clear difference in Russian language between question and statement, and unfortunately this course fails in this regard
Already answered elsewhere within this discussion. Standard English does not use "on" here, even though Russian uses "на".
An exception would be when you specify some piece of music. "Do you know how to play Chopin's Piano Concerto No 1 on the piano?" would work.
Wiktionary for the infinitive verb form "уметь" at https://en.wiktionary.org/wiki/%D1%83%D0%BC%D0%B5%D1%82%D1%8C#Russian is quite clear that this is about knowing how to play the piano.