Hi i am from B.E mechanical background want to do cloud computing tell me

Cloud computing has two parts to it - Coding and Admin. Admin is more like systems administrator and coding is more like managing and write software. I would recommend start with beginner books, start understanding basics, talk to local people to get involved with local groups. If you're in Delhi, get involved with local chapters and talk to people who are doing the same. 

Read articles, and get help here on forums!

Good luck!