parallel execution in multibrowser .

Hi

I would like to understand the steps to do parallel execution of testcases to save your execution by doing it in multi-browsers .

for example i have 3 class files in which i have testcases .

class 1 has login and logout methods to be executed in browser 1

class 2 has methods of application functionality to be executed in browser 2 but it has to call login method

class 3 has methods of application functionality to be executed in browser 3 but it has to call login method .

please tell me the steps of how to do this kind of execution .