Bees are often pre-ordered. I think you would be fine starting a hive when your day time temps are regularly above 13C - 15C or so - probably April to May depending on your altitude. I would ask local beekeepers, suppliers or local bee clubs what they think. I wouldn't mention the Flow hive to start with, just say you want to get a new hive started, and most people will willingly help you.
The Flow hive is just a new way to extract honey, all other aspects of beekeeping are the same as they are for your neighbouring beekeepers.
All the best, eh?