你总会从一个中央焦点or centre line . You could break the rooms up and do them individually however any good floor layer will be able to explain the best way to lay it and that in some areas it will have to fall where it falls

Best to ask a trusted tradesman, they will be able to suggest how to lay the floor so that it runs nicely throughout.

It is about time, budget and likeness; to many people would prefer if it is set up in a way that will run continuously into rooms as well, always focusing on departing point (center or the most trafficked area) with a edge surrounding all area where the floor will be laid, other people like to breaking into rooms personally it will look better as continuously throughout the all area, as it was done before any partition went up. I've pictures in my profile to show you better how it looks.

Make sure you employ a proper floor layer (not a handyman) ask them to pop round prior to fitting to ask them about your worries , remember on a job like this your paying for the floor layers experience and expertise not who’s the cheapest quote