Ok let's review things in more detail...
1) The left sidebar on Hum is the equivalent of the header (on more conventional themes): it can display a header image, the blog title and tagline, and a navigation menu. The regular menu automatically displays links to all your published pages; you can replace it with a custom menu that can display links to anything.
2) Hum does not have a sidebar for widgets. It supports footer widgets only. What it calls "Main Sidebar", "Showcase Sidebar" and "Footer Area 1/2/3" should have been called "Upper Footer Main", "Upper Footer Showcase" and "Lower Footer 1/2/3", respectively.
3) If you add widgets to the so-called Main Sidebar, they'll show up on dynamic pages (main posts page, category pages, other archive pages). If you add widgets to the so-called Showcase Sidebar, they'll show up on the showcase template page. If you add widgets to the so-called Footer areas, they'll show up on dynamic pages and single posts, as well as on any static page for which you select the "sidebar" template.
4) You can't change the position of the widget areas, except if you have the Custom Design upgrade and experience in CSS editing.
In short: if you need a sidebar, you need a different theme.