First of all, we have to clear NQT(which usually takes place in TCS ion center) to reserve a seat in TCS limited. Adequate resources have been spread across different web platforms. So it will be worth spending your time on that kind of websites especially when you are in mid of the placement festival.
After evaluation of NQT, they group you either under NINJA or DIGITAL. We have to clear another test(a bit difficult as compared to the previous one) for getting an interview call for digital. Try your level best if you get that opportunity. Even if you failed don't worry, you would surely get a chance to appear for ninja interview.
Ninja interview usually takes 15 to 20 mins. (I've actually appeared for ninja and I am from Mechanical background). There we have personal HR, Managerial HR, Technical HR(i had been interviewed through skype). That's the end of the TCS selection process.