Oh Dear, oh Dear, this exceedingly well-known song does not go like this. Teacher Tsang teaches you all the notes. The key to this tango, however, is the rhythm, lilt or you might say, groove. It must make you want to get up and dance. After you have got the rhythm in the left hand right, work on the singing melody in the right hand. Listen to how guitarists create nuances in the melody and make it breathe. Lastly, work on the middle voice to make it different from and complement the melody at the top. Daniel Barenboim, the self-regarding conductor residing in Berlin, was originally a pianist from Argentina. Although the melody is more Spanish than Argentine, he has the full measure of this deceptively simple piece and can make it sound orchestral.