The piece
The words, "Guten Abend, gut' Nacht", come from the folk-poetry collection Des Knaben Wunderhorn. Brahms set them for his friend Bertha Faber when her son was born, and published the song as one of his Five Lieder, Op. 49. The original is for voice and piano; this arrangement, written for Noctave, keeps the melody in the right hand and reduces the left hand to one held bass note per bar.
The tune opens with two pickup eighths on E, which should lead into the downbeat without leaning on it. The dotted quarter followed by an eighth comes back often and creates the rocking motion, so hold each dotted quarter for its full length. The tricky moment comes in the second half: after two pickup Cs, the right hand leaps a full octave to the high C. Prepare that jump during the eighths, hand already open, so you land on the note smoothly. Play everything softly, as the score marks it, keep the bass even quieter than the melody, and let each low C, F or G ring for all three beats.