You can now write the piece. You will first compose the rough one. It will be written and may or may not, depending on teacher instructions, be turned in to your teacher. I usually have several rough drafts before I get to the final. You should not be worried if this is the case for you. It is as it should be. A paper that does not improve is a bad paper. Once you turn in your rough draft, some teachers will mark it for you, and then let you correct it before yours is submitted. Ask your teacher about this process. And good luck!
Know what the teacher expects for you to submit. I ask for an electronic copy and then in hard copy form, I want all the printed sources, the outline, the rough draft of the paper, and the final draft of the paper.