Hi,

Please go to Appearance > Customize, then navigate to:

• Homepage > General: uncheck on Enable Two Sidebars On Homepage and Enable Left Sidebar On Homepage,
  
• General > Category, Tag, Search, Archive Layout: uncheck on Enable Two Sidebars On Homepage and Enable Left Sidebar On Homepage,
  
• Single Posts, select sidebar layout on Single Posts Sidebar Layout
• Page > General, select sidebar layout on Page Default Template Layout

Regards,
PenciDesign.