Firstly they call you on telephone and on that basis they decided interview date . And then he will contact you .and if you got selected then they provide offer letter immediately .

One to one interview first with hiring manager, then HR. Previous experience, analytical skills, education, why do you want this job, etc...very typical questions have been asked. All were expected, usual questions. If you are good at your job and have strong technical skills, there is nothing to be worried.