I also wrote a personal essay when I was applying. The most important thing is to be yourself and not make up stories. This is not an analytical essay, but a story about you. Read the article here -
https://www.ozessay.com.au/blog/personal-essay/ - it is very clearly explained what it is. It helped me understand that you need to not just describe an event, but show how it affected you. The main thing is sincerity, structure (introduction, main part, conclusion) and specific examples. You can start with a story that changed your view on something. Good luck to you!