Well you asked this question specifically from Abhiud, but would like to share my experience with you. I think the process must be same throughout the country. Myself and my husband both had the same query and we called up on their helpline. They said that no appointment required. You can directly head towards vfs global with the documents mentioned in the PPR email. The documents involved PPR email's printout for each candidate, consent form for each candidate, the consent form must be signed by the candidate whose consent form that is. You can sign that in front of them or you can sign it before going there, signature to be done by parents in the consent form of a minor. The Size and number of photographs as instructed in the PPR document. Original passport, two copies of first and last pages of each passport.
I hope it helps. But would recommend to speak to their customer care executives for better assurance. They guide you really well.
Thanks