Actually I was trying to understand how to launch an attack, for that purpose we require coding , so I wanted to know where can I get a start ?
It depends on the attack that you want to launch. If you don't know how to program, I would not recommend trying to do this. You will need to know how to do network stuff and sending bytes over the wire. You also need to know how Bitcoin networking works and how Bitcoin itself works in order to find viable attacks.