First you will finish your NATA examination and then on the merit score obtained in the NATA exam depending upon that after that you'll apply for CEPT AHMEDABAD. 50 percentage boards HSC marks of all the subjects are considered and 50 percent marks for NATA are concerned.

Refer the site below for more detailed information..

https://www.careers360.com/university/cept-university-ahmedabad

Best wishes. Thank you.