“Home” → “School” → “Create a timetable”. Open “Bells” and set when the first lesson starts, how long a lesson and a break are, and how many lessons there are — the bells are worked out for you.
- One break is longer (say, the big one after lesson 2) — the −/+ buttons under it: only the lessons after it move.
- One lesson is shorter — tap it and change its length; the lessons after it move along.
- The time can be typed too: tap the first lesson's time.
- “Add short-day bells” — a second set for shortened days.