On the main screen, each subdivision has a slider. By default, a slider controls the "probability" that its subdivision will play. When a slider is at 100% the associated subdivision will always play. At 50%, the subdivision will play on average about half the time but at random intervals. This means, for example, that if you set a quarter-note subdivision's slider to 50%, the subdivision might play on beats 1 and 2 in the first bar and on 2 and 4 in the next bar.
You can exploit this feature to build up your rhythmic independence, using the metronome as a hint and a guide rather than a constantly-clicking 'conductor' that you follow like a normal metronome.
If you prefer the sliders to control volume instead of probability you can change the sliders' role in the app settings.