the NCIE comes in 2 variations, SAN and Backup. It's the Implementation certificate, meaning on a configured cluster you implement SAN or Backup features.
the NCSIE is the installation certificate, meaning you're able and certified to build a cluster according to NetApp best practices. Hardware, racking, stacking, cabling.
Also proving to the customer, that everything works, by creating simple SVMs and knowing enough about NFS/CIFS/SAN to connect customer machines (maybe your notebook) to show the customer, that the stuff he ordered is actually working. Takeover/Giveback, Switchover/Switchback. Basic knowledge about the User Interfaces (CLI/GUI) to be able to answer typical customer questions (Where do I find... )
There are NetApp University courses to prepare for the NCSIE: COIW (Clustered ONTAP Installation Workshop) which I also teach 🙂