Arrangement of Blocks; Default page layout

Hello:

I know the basics of Drupal. I know much less about Panels, Skinr and Views, so I apologize if this question is really a question about them.

I notice that when I go to Administer > Site Building > Blocks, the blocks that render by default in Open Church are disabled. This suggests that their rendering is configured elsewhere. If I wanted to turn off some of these blocks, or change the order in which they render, where would I do that?

Also, could you point me at some documentation that explains how I might change what renders on that sidebar depending on conditions?

Thanks.

Mike