First things first: when you've been summoned to the court, you should always come on time. It's very likely that your case will start later than scheduled (usually because of the previous case lasting more than predicted), but if it does start on time, nobody will wait for you if you're running late.
When you've found your courtroom you'll be waiting outside of it together with other people involved in your case or just random people waiting for their cases to be called in the neighbouring courtrooms.
When the time comes, a court reporter (court clerk) will walk out of the courtroom and loudly call your case (they can also do it via speaker system). Usually they'll say something along the lines: "The case brought by Mr/Ms X against Mr/Ms Y" or "The case of Mr/Ms X for payment/divorce" or "The case of the accused Mr/Ms X". Then you enter your courtoom.
Upon walking in you'll see a a judge (or even 3 judges) sitting behind a bench (the biggest desk in the room) and two smaller desks put opposite each other in fron of the bench - you'll be sitting at one of them.
If it's a civil case and you're the plaintiff/claimant, you'll be sitting on the judge's right-hand side (which means that it'll be your left-hand side when facing the judge). If you're the defendant, you'll be sitting on the judge's right-hand side (the right-hand side from your perspective, when facing the judge).
In a criminal case, the prosecutor always sits on the judge's right-hand side, and the accused on the judge's left-hand side.
When you've walked in, you should sit by your desk and wait for the judge to check the attendance (do a roll-call). When the judge says your name you should stand up (every time the judge talks to you, you should be standing up, the same applies to when you're saying something to the judge). You always address the judge as "Your Honour".
After the roll-call, the judge asks each party about their position on the matter and very often about the possibility of reaching an agreement. If no agreement can be made, the judge will start hearing the witnesses, who enter the courtroom separately to give their testimonies. After the judge has asked a witness all his/her questions, each party can start cross-examination of a witness (ask the witness whatever is left to ask)