How to adjust Nokia 1661 cell phone volume ?

If you have a Nokia 1661 cell phone (don’t know whether other Nokia phones might same ), you maybe find it is NOT easy to adjust the phone speaker’s volume.

You can not find a setting item in the setting menu, either the speaker aloud setting item is not for the volume adjust case.  also the Tone settings is not either, So how should we adjust the cell phone’s volume ?

I only figure out this way : when the cell phone’s speaker working ( for example: you are talking with somebody, or you dial a number to listen something – you better dial a free number  : ), you click the right or left (Not up and down buttons) buttons, you will see the volume adjust interface !