Thank you for the opportunity to help you with your question!
The essay is always the first part of the SAT exams. There's tons of practice ones just online to help you prepare. Since the writing portion is 800 points out of 2400, it's worth 33% of your score. (800/2400=.33) Best of luck to you! :)
Please let me know if you need any clarification. I'm always happy to answer your questions.
The essay is actually apart of the writing section, included into the 800 points. The writing section is a combination of the essay and multiple choice questions. The actual essay itself is roughly 200 points of the 800 points for the writing section.