Promo effect and lift in Causal Forecasting

Hi,

I am running causal forecasting at the level of week/item/store. I have 2 promotions (boolean) created - promo 1 at day/item/str and promo 2 at day/dept/str.  During the period that causal forecasting is run - the only promo 2 is active. A promo effect (in promo effectiveness workbook) for promo 2 is calculated for the week/item/str, but I am not able to understand how that effect is converted to promo lift unit in the forecast.

I do understand that promotions cannot be aggregated across any other than across time. So how does causal calculate an effect at week/item/store for the promotion set up at day/dept/store level ? Also how does that effect translate to the promo lift in the forecast? I have not set the higher causal intersection.