I think you should choose the historical figure by yourself, but I'll try to help guide you on the rest.
You should include firstly who you chose the figure. What about the person captured your attention and why do you like them. Did they accomplish something that you admire? The personality contributes to the story however you want it to. If you want the personality as a main character of your own version of the story, you could do that. Fiction is about making the story the way you want it to go. You can play on the freedom there. The plot can be focused on achieving a goal or learning about life, or even finding a lost one. Sorry that last part sounded unhelpful. But really you can make it whatever you want. Feel free to comment on what you don't understand, hope it helped even a little.
