How to plan the interface screens of a simple application?

Question

User interface

Question for UI/UX gurus: how do you approach the task of creating an interface, what is the methodology besides intuition/experience?
It's a simple task. The user (logs in) fills a two-level list. 1st level is a group of elements of the 2nd level. Email 2nd, they are checked on a third-party service, receiving a yes / no answer for each element. "No" requires attention and some action from the user.

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Абстрактно для примера: 1-й уровень это Помещения, 2-й уровень – Датчики в помещении.
Если срабатывает один из датчиков, Пользователь свяжется с ответственным за Помещение: отправит сообщение в мессенджере или ещё как-то.
Заводим Помещение, добавляем в него Датчики.
Приложение и его состояние индивидуально для каждого отдельного пользователя.
Состояния Датчиков проверяются при запуске приложения, при добавлении, и можно инициировать проверку вручную через кнопку или пункт меню. Но обычно будут запускать приложение раз в день-два и проверять. Чаще не требуется.
Не автоматизируются действия в случае срабатывания Датчика – надо только выявить и показать Пользователю, далее его действия оффлайн.
Приоритетно минимизировать действия. Открыть приложение; если что-то не так – понять, с кем надо связаться.

Option A. Push everything into one screen, a list of the 1st level. On click, the element expands and shows its 2nd level. Somehow show already on the 1st that there are "nets" inside that require attention. Hanging button (+) to add a new element of the 1st level.
Option B. Show some kind of dashboard with statistics. Either "Everything is in order" or a list of problems - each link to an action. Separate screens for the 1st level list with a form for creating a new one, and by clicking the transition to the screen of the 2nd level list with the form for adding elements as in todo-list.
Option B. How to actually do it perfectly. But I don't know him)
How to systematically approach the creation of an interface? Input data: list of entities, list of possible states and actions.

Answer 1

More details are needed to solve this problem.
Those. we have Level 1 Tasks and Level 2 Tasks.
Action to create a Level 1 Task, but how is a Level 2 Task created?
Will it be filled by one person or several?
Everyone has his own personal account and he sees only his own tasks, or is there a multi-user option, when several users will put different tasks into one conditional folder?
Who will review Level 2 Tasks?
Why will tasks of the second level be checked, but what about the first?
Next, we need to understand what is more priority for us:
1. View Tasks 1 or 2 levels?
2. Identifying problems and observing general statistics?
3. Filling the platform with tasks?
More or less like this. From all this, you can make a targeted decision that will meet the needs of the product.
Have a nice design...