Ok when you get the nuc set your hive up and place both side by side, the important bit is the entrances both pointing the same way. I’d pull the plug on the nuc and allow to settle for a couple of hours. This just reduces a big cloud of bees buzzing around looking for home when you open up.
When ready just transfer bees/frames across in an ideal world ask for the queen to be marked she may already be. Put the frames in the same order as they came out the nuc and hopefully finding the queen in the process. If you don’t see her check the lid/box! To remove any bees in the box once you checked for the queen, simply give the box a quick rap knocking the bees into a corner and pour in

Keep the brood next to the entrance and the entrance small. Fill the box with additional frames.
You should get an idea on stores when you transfer, I’d suggest if they have less than a complete frame of stores even spread between all frames a little feed then is required. It’s simply a case of of adding the crown board an empty super if needed for the feeder and roof.
The following week check for eggs you don’t need to find the queen although it’s nice! I’d then consider adding frames of foundation up against the brood nest. So if you have say 1 frame of solid stores I’d slip a frame of foundation in between it and any brood. Don’t split brood.
If the weather is good there may be income/nectar so you will have to judge, just don’t feed gallons. Little and often even a pint would keep them kicking over between weekly inspections. You should find they’ll readily expand onto your new frames, when there’s bees covering say 8/9 frames in the new box you’ll want to add another.
This is just a guide re space and feed if in doubt in both instances you won’t kill them by adding more but don’t just do it needlessly. I’ve seen beginners let nucs starve in poor weather and some feed until they’re rammed and swarm!
Good luck!