The play, Much Ado About Nothing by William Shakespeare, can be a confusing play. Being one of Shakespeare's comedies, it relies on the people in the play for the humor. When your teacher says that the guards are for relief, your teacher means "comic relief." When a play has a very intense scene (think of something in a scary movie with the music very spooky and you not knowing what will happen), the audience is sort of holding its breath waiting for what will happen next. To break up the tension, the guards provide comic relief as comic relief lets the audience laugh and get ready for whatever happens next. So, your teacher is trying to show you that intense right next to comedy is a good thing. What you need to do now is to talk with your teacher and let them know that you are feeling lost while reading this play. Try to figure out what you don't understand and write down the questions you want to ask. If you are paying attention in class and doing your assigned work but still don't understand, teachers are usually quite willing to help those students putting in good effort.