In the Player controls:
iOS, Android: tap on the Mixer button (second one from the right at the bottom of the screen) to change the Count-in settings.
Mac: the Player controls is the right panel. (View menu>Maximise/Minimise Player controls).

Select zero for No count-in or set the volume of the count in with the slider.
You can also change the click sounds.
The Auto setting will automatically play one or two measures - depending on the tempo allowing more time for faster tempos before it starts playing.
(iOS, Android: in case you can't see the count-in when you open the mixer, scroll down to reveal it.)