There was supposed to be 2 interviewers, manager, supervisor but it became the supervisor and HR.
the interview was formal, the company has a sheet of questions that they would ask you on.
They would go through the list from top to bottom and end the interview from there.
They did not list confined space certificate in their requirement, but they asked for it during the interview.
There is probably going to be a second interview as not many details were shared.