Hi Caitlin,
A local mentor, as Jeff’s suggested, would be a great idea, as they will understand your local conditions and how this impacts on your colony, better than we could ever hope to from here.
Your bees can remain in the nuc for a few days (at least one is good). Sit it atop the brood box in the meantime (which in turn will be positioned on the base).
To install your nuc, pop on your protective gear, puff some smoke, gently lift the brood frames from the nuc box, and place them in your new brood box. You’ll need to ensure that the frames are placed in the brood box in the same order and direction as they were in the nuc. I’d put all of the nuc frames to the centre, with your added empty frames on either side, but as an alternative, if you’re in a warm enough climate you can checkerboard the frames in the brood box to support straight comb building i.e. a blank frame in between each drawn frame.
Take your nuc and hold it above the brood box, tap gently to encourage the remaining bees into the brood box.
You will notice the frames leave a little wriggle room and may think you need one more frame - you don’t. Just push them all towards the centre of the box. You’ll need this extra room at either side for easy access come inspection time.
Pop your inner cover and roof on, and if you wish, place a small branch in front of the entrance (this will let the bees know something has changed in their environment, and trigger them to reorient themselves).
Let them settle in for up to a week or so before inspecting the brood box, and be sure to wait until the brood box is well established and completely pumping with bees before adding your super.
If you are using foundationless frames, you will need to inspect the hive a couple of times as the brood frames are established, to avoid cross-combing, and correct them if needed.
You’re on your way… happy beekeeping!