Telephone based interview. Depends on which group you work in. If you are suitable then you get invited. But once you are invited the chance is 70%.Try to be as relax as possible and know more about your past experience. Be a person who suggest ideas. Usually the PI will roll you to each group member so you can also get to know the real situation of the lab. Try to ask them without the presence of the PI if possible in some private place so they can tell you if it is a good idea to work in the group or not. Usually the impression from the group members will influence the hiring decision.