3/4 time is "strong - weak - weak" — three beats per bar, one step per bar in a waltz. It is not just 4/4 with a beat cut off. The pulse feels circular rather than square: every bar returns to the same starting position, which is why waltzing feels like turning around your partner instead of progressing across a floor.
This page is set to 100 BPM, 3/4, traditional drum — clear downbeat on beat 1, lighter on beats 2 and 3. If you are learning the box step, the downbeat is the first step; beat 2 is the side step; beat 3 is the closing step back to where you started.
100 BPM is the right beginner speed. Viennese waltz goes 130-180+ BPM, but that is a different skill level. Stay at 100 until the "strong-weak-weak" feels automatic, then push.
The app pre-sets to 100 BPM, 3/4, traditional mode. To adjust, use the controls inside the app after it loads.