Arsen -
See the NSO 145 Cert page:
http://www.netapp.com/us/services-support/university/certifications/ncsa.aspx
Take the web trainings (WBTs)
If a command is mentioned, then study it.
Try the practice exam when you think you're ready.
Practice the commands on a sim, and read(study) the man pages !
Enjoy !
I hope this response has been helpful to you.
At your service,
Eugene E. Kashpureff, Sr.
Independent NetApp Consultant, K&H Research http://www.linkedin.com/in/eugenekashpureff
Senior NetApp Instructor, IT Learning Solutions http://sg.itls.asia/netapp
(P.S. I appreciate points for helpful or correct answers.)