To hide your navbar and header logo on in your blog index, please edit this page and change your page template. Instead of using the default page template, use the Blank Container | No Header, footer page template. To disable your breadcrumb, you may go to your customizer, Appearance > Customize > Header > Miscellaneous > Breadcrumbs. If you only want to hide the breadcrumb in your bog index, please add the following css code in the customizer, Appearance > Customize > Custom > CSS