There are many formats in which you can share your story. Remember that the purpose is to reflect on what the story meant to you as much as on how/what you remember.
Length
Whether you write it, record it (audio or video or a photo collage), keep it at the length that would encourage others to fully engage with your story and read it/listen/view it completely. My recommendation is thus that you keep your blog posts between 500-700 words and your recordings under 3 minutes (that is actually 250-350 words at a moderate reading pace).
Structure and script
There are various ways in which you can tell your story, various “script” structures you could use. The most popular one is perhaps the hero’s journey, one in which you, as a protagonist, tell your story of transformation and discovery identifying your mentors, supporters and villains/opponents along the way. The other is to start immediately with the action – this is the 4c structure (start with a sentence that connects the audience, continue with 2-3 sentences for context, use another 2-3 sentences to show the change and bring closure in another sentence).
Always start with your notes
If you chose an audio or even video format for your story, always start with drafting the script – that is writing the text out. Fill it out later with the images that you feel complement or add to your story.
Give it a try and enjoy the experience of revising your volunteer memories.