It tells you which step would never have arrived

A flow fires on something that happened — a COD order, a failed delivery, a parcel turning back — and runs without anybody watching. Drag the steps in, or write one sentence and let it draw the rest. The part nobody else does is the check it runs while you build: WhatsApp accepts a message sent outside the 24-hour window and then never delivers it, so a broken flow looks like a working one until a customer says they never heard from you.