Eclipse - ButtonCLick --->Go from one .xml layout to another .xml layout

I am looking for a solution in Eclipse. I have a main menu with 5 buttons which I plan on linking with another 5 .xml Layout but I do not know much on programming and Eclipse.

In which files I should add code that will take me from main.xml layout to another with a button click.

I head read previous post with similar topic but the answer does not say were exactly to allocate the code.

Try this code.

[1] call startActivity to open another layout.

startActivity(new Intent(getApplicationContext(), _second.class));

[2] Create another XML layout file which you want to display.

[3] Create new class and give it the name like "_second.java"

    public class _second extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); setContentView(R.layout.second); }`

 }

That's it.

I understand the point 2 and 3 and how to do it but in which file exactly do I have to put the 1st section of code? startActivity(new Intent(getApplicationContext(), _second.class));

For all answers I kindly thank you.