First interview was with HR and they ask you about your history, what you are looking for in a role. Then they decide whether you are suitable for the role you applied for and if they have anything available. The next stage is to meet with line manager at HQ and this interview is also about your work history, work style about the role, etc. The difficult part is waiting to hear back between each stage as HR seem to take their time to get back to you and you have to chase.