I have a quandary. I have heard to purchase the bees, build up the swarm, and wait one year to harvest honey. The other side says if you have a Flow Hive you can get a harvest of honey first year.
My situation is I purchased a five frame nuc from a local apiary and have the Flow Hive. Do I allow the bees to build up or can I harvest this year? Let me know fellow bee keepers.
Thank you.
Impossible to answer without a clue of your location in the world. 
Your avatar has a sort of derivation of Old Glory (the American flag), but that still doesn’t give us any clues about your climate or nectar flow.
Have you joined a local bee club? What do they say about new hives? The Flow hive is just a different extraction method, everything else about looking after the bees is the same. Do they use 2 brood boxes for overwintering the bees. Have you already put the Flow super on top? How full is your brood box? So many questions before we can help you accurately… 
P.S. Bees happily installed inside your hive are not usually called a “swarm”. They are a colony! 
They are a swarm when they have decided to leave the hive and are looking for a new home.
Actually looking back at an older post of yours, you really need some local input. Winters of -40? Wow. You probably need at least 3 brood boxes, what do you think @Anon? You probably also need to insulate them all, and have a quilt box on top.
That makes me think, no Flow super for you this year… 
Great thanks. I will definitely get some more brood boxes for the winter. And yes we do get to -40 for up to two weeks straight. I appreciate the information.
OK, you didn’t answer any of my important questions, so let me tell you now…
Take off the Flow super if it is on the hive.
Fill new brood boxes before you put it back on. Only add them when the lower boxes are FULL of comb, and the comb is 80% FULL of food or brood, AND every comb is COVERED with bees. If you go faster, the hive will not be able to defend itself from robbers and pests. OK, rant over. 
That’s no rant. That’s good advice. Alot of people struggle with the required patience and don’t take hive location into account; if you read posts from Australian beeks you’ll see extractions in the first year so that gives hope for many…until you realise the location and conclude it’s probably not the norm.
It really depends on your goals:
Start feeding them after removing the Flow Super and adding your next brood box until you get to three deep brood boxes or…
go ahead and harvest now with only a single brood box, let the bees starve out in winter, and buy new bees next Spring. Those new bees can use the old comb to get a head start. Once they get two brood boxes completed, add the super, harvest, let those bees starve over winter, and repeat until you have three brood boxes.
