New to Computer/Digital Music Need Help NADM15

Recently purchased NAD M15 HD pre/processor. Want to get use my macbook and for now itunes library. Struggling with what I need to accomplish this. Questions are:
Is the onboard DAC adequate or can I use an external DAC? recommendations?
What is best way to connect macbook to NAD unit? Headphone jack? USB with external DAC?
What input do I connect into NAD? Any help with configuring setup menu based on connection method?

I recently purchased MAC Sound Pipe but cannot get sound. I assume this is teh "poor man's way" and do you recommend a SPDIF bridge assuming use of an external DAC? My price limit for teh DAC would be <$600.00. Thank you for considering to help.
see how I am configured. this is a typical setup. don't know your NAD piece but if it has an internal DAC you can use that if the sound pleases you. You need to set the computer to make the NAD DAC the output, if you use a usb cable, shortest is better. Pure Music App is recommended and recording in apple lossless with error correction turned on.
I don't have any direct experience with your NAD M15 but according to the specs on the NAD site it has four optical digital inputs.

If your Macbook was made within the last decade it almost certainly has a mini-Toslink optical output available through the headphone jack. The simplest possible connection would be to get a Toslink cable and mini-Toslink adapter for the Macbook end. Plug the other end into the NAD and I would think you'd be set.

Can't help with whether you'd need to select and configure that input on the NAD, though. The DAC in the NAD is almost certainly much better than the one in the Macbook. Be sure to check the manual on how the optical inputs work.

USB out of the Macbook and routed through a USB DAC is also an option. There are a number of well-thought-of inexpensive DAC's like the Musical Fidelity V-DAC and the Nuforce that would make the connection. I use an Aune mini-DAC in my office with an iMac USB connection and it's very good.
Larryken. thanks for helping me out. I have downloaded PureMusic app and begun converting files.

Sfar I went to a local Apple retail store and the first person that helped me told me that the head out jack was regular audio on a macbook an dthat they did not carry toslink with adapters for the mini jack. Then visited another store and asked again sharing your note and they agreed and located the cable. Also exploring an external DAC. Tahnks for your help as well.