A personal narrative essay is about a personal experience of yours, so the essay is generally written in the first person. You are certainly welcome to write about your experience in the third person, but I do not recommend it. In order for the essay to have the most impact on a reader, the essay should try to have an emotional impact on the reader, include vivid imagery, and make references to how you perceive the environment with your senses. Don't be afraid to explain inner emotions either.
To be honest, I think you have a tough task in front of you to write a meaningful personal narrative in five to eight paragraphs and include all of the things listed. That writing length could probably encompass most of the items; however, getting decent plot development and character development in six paragraphs is going to be tough.
Regardless of how much you are able to pack into the essay, it is critical to start with something that is going to catch the reader's attention. Additionally, because the writing space is so limited, you need to incorporate setting and character details right away. Think about moments in your life that have been relatively short but incredibly meaningful or memorable. They don't have to be poignant. It just needs to be something that you remember vividly because this essay is going to try and recapture that moment. Start with a bold statement, and move into setting and character from there. For example:
I knew it was a bad idea the moment my brother and I left the house. It was July 4, and we had decided to go shooting in the desert. That sounds like a fun way to spend the holiday except that we didn't think it through, and we didn't realize that until we found ourselves out gas, in the middle of the desert, with temperatures climbing to nearly 115 degrees. Sweat had long ago stopped pouring off of our bodies, and the heat was nearly able to take our breath away.
Continue through your narrative providing details in the order that they occurred, and finish the essay by explaining to your readers what lesson your story left you with.