NX CAD # tutorial 7.1#BASIC Tutorial
How to create core cavity, check this link
https://youtu.be/mMOjRMMU6Qg
NX 10.0 for Engineers and Designers (MISL-DT)
https://amzn.to/2mf6GiI
Mold Design Using NX 11.0 : A Tutorial Approach Paperback – 1 Jan 2018
by Sham Tickoo (Author)
Https://amzn.to/2kN0f68