Choose from the list from those allocated to your section or unallocated, copy and paste the text from a template like this into your sandbox, and start creating an article (if you see code click on the right to switch to the Visual Editor).
Look at an example of a biography article and try to cover the same information, formatting and structure, like this. or this.
Or if editing an existing article, go to the article, copy the section you want to add to into your sandbox and work on it there until it's ready to be added back to the live article.
