Eight decisions build a room. The rest follows from them.
6 questions every room needs answered, then two chosen for your room by rule — never more than that. The style comes after, because a design language is applied to a room that already works; it does not decide whether the room works.
Before the questions we collect 6 project facts — the room, whether it is a new build, and so on. They are things you already know, they decide which questions are worth asking you, and they are counted as no decision at all.