Helpful general information and advice for attending court can be found here - What to say and do.
Court witnesses give evidence from the witness box in the courtroom. Before giving evidence they are required to take an oath or make an affirmation to tell the truth.
An oath is a verbal promise to tell the truth made while holding a religious book (if you require a holy book other than the Bible, please advise the prosecutor prior to the court date).
An affirmation is a formal verbal declaration which has the same effect as an oath but does not use a religious book.
The prosecution lawyer (called the plaintiff’s or appellant’s lawyer in a civil matter) is the first to ask you questions about your evidence.
Another lawyer, either called the defence lawyer (representing the defendant/accused in a criminal matter) or the respondent’s lawyer (in a civil matter) then has the right to ask you questions. This is called a cross-examination.