There are 15 block regions with this theme that are collapsible (if no blocks are published to the region, it will not appear).

Logo, Toolbar, & Footer2 are conditional regions. There are other elements which occupy these areas, such as the logo image for Logo; the fusion menu for Toolbar and the copyright notice in Footer2. When you publish a block to these regions, it will collapse the theme element and replace with your block.

The below diagram is of the Block Variations page.