Help for Amatuer Writers

Hey, ya'll! I am an amatuer writer at best. Part time hobbyist at worst. I write short stories geared toward teenagers, mostly. And have only finished one. But my hubby has great faith in me and has asked me to write his story.
Wow! What an eventful life he has led! And what great faith he has in Jesus, as well! It would be a great encouragement, I believe, for others to hear his story.
But what a daunting task! Where to start? HOW to start? When he was badly burned as a child? When he received a prestigious award for his work in the fire dept? When he went into the refinery after it exploded and led his men to extinguish massive multiple fires when others backed out?
If any professionals or seasoned writers feel led to, I would appreciate some help. And I am sure other amatuer writers would love some advice, too!
I am feeling a bit overwhelmed. He had asked me a long time ago to do this, and I made a stab at it. But so much keeps happening in his life, I told him to slow down! I dont know how to end it! hee!
Thanks in advance.
Oh, and if this is inappropriate, or if this group is only for professionals, please feel free to delete this thread. I'm not clear on the rules and regulations.