Ok, now it's clearer, thank you.
Rather than the House of Matter we could refer to it as the house to which the question belongs. Maybe someone else has a specific term for it, but for the moment let's use this.
So, as you wrote, the sign on the cusp of the house determines the significator of the question.
If it contains planets, these would indicate either persons or events related to the question.
Depending on the aspects in the chart they could be approaching or separating, so we see what happened earlier or what will be happening.
And they can be identified depending on the question, what planets they aspect, what signs they are in.