Arrange your sidebar layout is as easy as drag-n-drop. To do this, simply click the "Sidebar Widgets" tab under the Layout menu.
You'll see sidebar components listed under "Available Widgets" - just click and drag them where you'd like them to be on your sidebar "block". If your chosen theme has two sidebars, then you've got two "blocks" to work with. You can add, remove and change the order of these widgets as much as you like.
And if you're thinking you'd like to leave your sidebar just the way it is, go ahead. Your theme comes with a default layout so no changes are necessary to keep your current layout.