I don't know that NAD, but you need to run an adapter from the line out RCA's to the input mini-jack on the Mac. If it has one. If it doesn't you need an adapter to USB plug most likely. The Mac also needs to be set to use that input, I like a little program called SoundSource which sets that from the menu bar.
To record you can use Audactiy which is free, but I much prefer Amadeus, which isn't expensive and there might be trial versions available. It will make a master recording, which you can then separate into tracks and burn a CD from or export to Mp3 or FLAC or whatever. You can do the burning part right from Amadeus.
You record just like you did with cassettes if you did that, click the record button and drop the needle and adjust your levels so it doesn't clip, do that part first if you know where the loudest spots are. Amadeus has useful meters which will hold warnings, so if you go away and come back and they are red, it clipped in there somewhere.
At the end you have a digital file instead of a tape, make sure you save it first, then split and name the tracks and edit out the longer dead spots. You can apply noise reduction and edit out pops by zooming way in and editing out fragments.