You should be able to get in to the CEPT Ahmedabad, but as per their official website, you should have passed 12th and should clear Jee Main - Paper 2.

They have to options, ACPC Seats and Open Seats which you can apply from : https://admissions.cept.ac.in/undergraduate/faculty-of-technology/bachelor-s-in-construction-technology

Once you apply you need to wait either for Merit or depend on the seats available when you apply directly.

The minimum eligibility criteria is 50% marks in 12th board and 70 marks out of 200 in NATA to apply at CEPT University.

50% of 12th score and 50% of your NATA score sums up to your merit.

There are total 80 seats for Bachelor of architecture, 40 for Gujarat students and 40 for All India students  entirely on merit basis.. You can apply in all India seats if you are not from Gujrat.