Yup.. Just go to the dias. And just say about you in a polite manner as following:

Hello Friends! This is ....your name... I am studying .... class in our school. As our school generally conducts essay writings and allocutions to improve our creativity and talking skills, Today we have an allocution competition here. For this, I have chosen a topic "The Children"  which tells about how the children are behaving in modern era etc ( about what else you are including regarding this topic)
2 5 2