The two menus and the slider under the title Start of measure note select the pitch and velocity of the note used to mark the beginning of a measure.

The same setup is available just below to specify the note used to mark each beat of a measure. In the case of a 6/8 measure, this will mark every dotted quarter note.

The same setup is available just below to specify the note used to mark each sub beat of a measure. In the case of a 4/4 measure, this is not applicable. In the case of a 6/8 measure for instance, this will mark every eighth note. By clicking in the By default button, Pizzicato will load the values best adapted to your synthesizer and will display them.

To enable the metronome for a given score, click on the "..." button of the score window tool bar and check the metronome check box.