Hi
To do PhD,

• Choose which college you want to do PhD in
• apply when the application form is open
• after getting shortlisted, follow through the selection process as per all the guidelines given

Some colleges do have a screening test before admissions into the colleges and PhD is done after masters from a recognized university or college, also there will be reservation for the admissions.
for fees structure, it depends on the college or the university you choose to get into. It will be between Rs. 2000 to Rs 2.5 lakh