[Theme: Twenty Thirteen] Creating a left sidebar?

I’m trying to add a left sidebar for the new Twenty Thirteen theme.

Functions.php:

function twentythirteen_widgets_init() {
	register_sidebar( array(
		'name'          => __( 'Main Widget Area', 'twentythirteen' ),
		'id'            => 'sidebar-1',
		'description'   => __( 'Appears in the footer section of the site.', 'twentythirteen' ),
		'before_widget' => '<aside id="%1$s" class="widget %2$s">',
		'after_widget'  => '</aside>',
		'before_title'  => '<h3 class="widget-title">',
		'after_title'   => '</h3>',
	) );

	register_sidebar( array(
		'name'          => __( 'Secondary Widget Area', 'twentythirteen' ),
		'id'            => 'sidebar-2',
		'description'   => __( 'Appears on right sidebar.', 'twentythirteen' ),
		'before_widget' => '<aside id="%1$s" class="widget %2$s">',
		'after_widget'  => '</aside>',
		'before_title'  => '<h3 class="widget-title">',
		'after_title'   => '</h3>',
	) );

	register_sidebar( array(
		'name'          => __( 'Third Widget Area', 'twentythirteen' ),
		'id'            => 'sidebar-3',
		'description'   => __( 'Appears on left sidebar.', 'twentythirteen' ),
		'before_widget' => '<aside id="%1$s" class="widget %2$s">',
		'after_widget'  => '</aside>',
		'before_title'  => '<h3 class="widget-title">',
		'after_title'   => '</h3>',
	) );
}

Sidebar.php:

<?php
if ( is_active_sidebar( 'sidebar-2' ) ) : ?>
	<div id="tertiary" class="sidebar-container" role="complementary">
		<div class="sidebar-inner">
			<div class="widget-area">
				<?php dynamic_sidebar( 'sidebar-2' ); ?>
			</div><!-- .widget-area -->
		</div><!-- .sidebar-inner -->
	</div><!-- #tertiary -->
<?php endif; ?>

<?php
if ( is_active_sidebar( 'sidebar-3' ) ) : ?>
	<div id="tertiary" class="sidebar-container" role="supplementary">
		<div class="sidebar-inner">
			<div class="widget-area">
				<?php dynamic_sidebar( 'sidebar-3' ); ?>
			</div><!-- .widget-area -->
		</div><!-- .sidebar-inner -->
	</div><!-- #tertiary -->
<?php endif; ?>

It works when I put widgets in but it’s overlapping the secondary sidebar which is floating right. I need the third sidebar to float left. I’m pretty sure I’m missing a step. My current site: https://rachelsilberman.com/MikeMullin/