Have you looked at the JMeter documentation? Have you searched the web for JMeter tutorials? How familiar are you with JMeter? If not at all, I suggest you go through a few tutorials first before you tackled testing your app, especially if your app is very complicated.
I am a beginner
But I try to googling and if I am not wrong if we want test a service we have to add class file to jmeter class path.
For my service I have many service mule and spring need to load so how I can test my service???