Conduct basic research. Depending on your story, you may feel you need to do in-depth research on a certain subject, like air force pilots in WWII or life in a refugee camp in Poland. However, resist doing too much research before you start your first draft. You may get overwhelmed by the amount of information you come across during your research and start to forget your personal take on the facts. Remember that your memoir should focus on your memory of the event, rather than be purely factual or completely accurate.
Either way, this jump is disturbing, but the description likely caused you to cringe more than the summary. And doesn't some part of you want to know what happened next? Who came to help? How quickly they reached a doctor? If all had turned out well in the jump, you would not have the same compulsion to read on. If you can't think of any details, write a line of summary and return to fill in the details as you remember them. If you remain relaxed about it, you will remember. If you don't, you don't. Writing an autobiography isn't easy, but it should be enjoyable.
Develop a central theme, main idea or thesis that clearly explains the purpose behind your autobiography. For example, your theme might be about how you overcame obstacles to become a stronger person, or it might explain why a particular passion -- such as mountain climbing or rescuing animals -- is so important to you. Back your theme with details and background information about your life experiences. For example, you might explain that your dad is in the military, so you've had to learn how to adapt quickly to new schools and unfamiliar environments. Or, you might discuss what it was like growing up in a poor, single-parent home, but how your family was always willing to take in injured or stray pets.