Professor Frankl comments the first movement of Beethoven's Piano Sonata in many musical aspects, such as dynamics, expression, phrasing or sound layers. In certain passage, it is necessary to reduce the intensity after the chord and then it is the moment to grow up, but not before. The left hand should avoid overlapping the right one. In general, phrasing is thought as a long line and not every two bars. Harmonically, all the changes must be prepared beforehand. About dynamics, the student has to control the progression of the crescendo in long passages (the crescendo grows up step by step). Professor Frankl also advises the student to pay more attention to rhythmical designs. In the Andante, the quite and calm character should be pointed out, but always in the right tempo, without ritardando. Finally, Frankl comments the correct tempo at the beginning of the development.