Hey
@NS Here's a brief tutorial on how to get a Restlet with Authentication set up (Netsuite side). Be warned though that the hardest part is getting a client side library that works. If you do it internally in an Excel macro, it will be very difficult. It's probably easier to use an external program create an Excel file for you or something Anyways, here you go:
https://github.com/MichaelEPope/nsrestlet/blob/master/tutorial.md