Need the code for my radio, Nissan Micra 1997?

Battery died! Got new one but can anyone tell me the code for my radio please and tell me how to accept it. For example i know how to input the code but which button actually inputs the code when you've done?

BP6340v3603211 and the other two numbers on it are 28 113-5f600 and 7 646340318

Anyone help??