Click on the "Edit" link at the top of your People page. If you are adding a new person, you can copy the entry for an existing person to use as a template. Don't forget to click on the "Save" button when you are done editing.
To upload a new photo, see "How do i add an image to the site?".
If you do not see the "Edit" link at the top of the People page, then you may not be logged in. See "How do I log in?".