How to transit and set up for two kids?

My first one will be about 18 months when our second one is born. Currently, helper sleeps with the first born. We have 3 bedrooms (master, helper + first born, study). Any advice on how we should set up once the newborn is here? We cannot seem to decide….we have a helper and plan to get a confinement nanny. Plan: - Nanny sleeps with second born, helper sleeps with first born for first month - Move first born (who would be 18 months) to sleep with us of blood bed in the second month. Helper sleeps with second born Would this be doable? Anyone any advice? Was also thinking of Plan B: 18 month old to the current ‘study room’ but am also worried if she can transit. Hence was thinking to put her in our room….