You are invited to one day of interviews where you talk about the labs research to the PI, everyone from the lab and some other PIs if asked to. You also talk to the PI of the lab you are interviewing about his/hers conditions and yours. They show you the building. All this day is payed by the lab. Later, when you accept and work there, you find out that some of your conditions can not be met due to management. Some PIs change their conditions with time. You have to accept or leave.