Answer:
The song is called "Row, row, row your boat." Rowing is a way of propelling a small boat without the use of a motor.
If you can play a B flat scale on your clarinet, you can play this tune, which has a range of one octave. You play the low B flat three times, then C and D. Then you play, in succession, D, C, D, E flat, F. Then the high B flat three times, F three times, D three times, and the low B flat three times. Finally you play a little scale downwards: F, E flat, D, C, and the low B flat.
That is sounding B flat of course. It is written (assuming you have a B flat clarinet) in the key of C, where the notes are: C,C,C,D,E; E,D,E,F,G; C',C',C',G,G,G,E,E,E,C,C,C; G,F,E,D,C.